Visitor Visa - B2

Hi,

Recently my parents had applied for B2 visa and got rejected under section 214B.

VO: Whats purpose of your visit
Parents: convocation of our daughter

VO: who is funding her
Parents: me (my dad)

VO: What is your profession
Parents: Dad- Retired as a bank manager, Mom-Housewife

VO:Apart from your home do you have any other property
Parents: No

VO:Do you have club membership
Parents:No

VO: Do you have children apart from your daughter
Parents: No

VO: Do you have parents
Parents: Parents are not alive

VO: Can't approve it

My husband lives in US and he funded my education. He is on H1b Visa. I was married to him 2 months prior to my visa interview and was not having marriage certificate. So while giving visa interview(F1) I had mentioned that my dad is going to fund me and I don't know anyone in US.
That's how my dad got confused while giving an interview and said he funded it.
(Note: My dad has enough fund in his bank account to sponsor)

From my perspective, this case seems as potential immigrant to VO.

1.Could you please give suggestion about how they can overcome this denial and show sufficient ties to the home country to show that they intend to return.
2. Also, what will be good time to re-apply to increases chances of approving visa.

Thanks in advance !!!