Visitor Visa - B2

My parents visiting visa got rejected two weeks back in Hyderabad.The interview is in Telugu and no transalators, VO asked the questions in Telugu.
I sponsered visa to my parents. Iam pregnant and my due date is in March. So I would like to have my parents during my delivery. (But I did not mention about pregnancy lastime when they went to visa interview. I just mentioned that I would like to show them some places here) Though Iam sponsered visa to my parents, my parents brought all the property documents, family photographs. But the VO did not asked them many questions and gave 214(b). Here is the interview questions:

Parents:Namaste
VO:Namaste
VO: why are you going to US?
parents: TO see my daughter and some places.
VO: What is your daughter do?
Parents: Software Engineer
VO:Which company?
Parents:They told my company name
VO:Where will she stay?
Parents:They mentioned my city name
VO: What is your Son-in-law do?
He is also Software Engineer in the same city.
VO:Which company?
Parents:Do not know(I did not tell them my husband company name because Iam sponsoring, I thought they do not need my husband details. so I prepared them only with my details)

VO: How many children you have:
Parents: two, one daughter, and son
VO:What is your son do?
Cultivation
VO:What is your occupation?
Cultivation
VO:What is your income?
Parents:3 lacks per year
VO:How many months you are going to stay there?
Parents: 5 months
VO:Do you have your daughters tax returns
Parents: My dad gave him my w2 forms(I have sent them my last four years w2 forms)
And then he said we are not giving visa and gave 214b form. stated they VO did not convinced that they will return to India.

Same VO officer have given visa to 4 couple before my parents. He did not ask them more than 3 or 4 questions and gave them visa and rejected my parents.

Also, my parents has to take care of my grand mother (mom's mother and she is 68 years old). My parents has all the property documents, and photographs of my grand ma and their grand children to show them that they have strong ties in India to come back to India. But VO did not asked them any questions on that and not even a single document.

We are planning to send them again sometime in next month. My dad do the cultivation but he has the business plan but he did not get the license by the time we filled DS-160. So last time, we selected Agriculture as his occupation when filling the DS-160. Now he has got the license for his business and they are going to start the business in a week.

So my question is,Can we select the business as his occupation now to fill the DS-160 form.(We can select only one occupation). Will it be a problem if it did not match with previous one

Since they gave 214(b) and stated that VO did not convinced that they will return to India. So we would like to show my dad's business and tell them that they need to go back to India to take care of the business and also my grand mother.

But we were thinking will they compare previous application and occupation and if it did not match will it cause any problem?

Also, if the VO asks about my pregnancy this time(last time they did not ask that question), Can my parents say NO? I am not mentioning about my pregnancy in the invitation letter. Iam just mentioning that I would like to show them some tourism places. Most of my friends are suggesting not tell about pregnancy.

Also, we are selecting only 3 months duration for their stay this time? Does this needs to be matched with previous one? Previous they said 5 months to the VO and we also selected intended duration 5 months in the DS-160 form. Does this needs to be matched?

Any suggestion and help would be appreciated.