Visitor Visa - B2

Please Sir/ma I need your assistance, i went for my interview on 19th January 2016 and my visa was refused, i applied for b1/b2. Am a Firefighter from Nigeria, 34yrs old, married with a kid, my monthly salary is around $752, i want to visit my instructor (citizen) to learn more about my job for 2 weeks during my annual leave which will commence by early March this year,i have all the documents with invitation letter to back my case but the Consular Officer did not even ask for any document, just two questions. The interview goes this way:

1,VO: Good morning
  me: Good morning sir
2,VO: Why do you want to go to US?
  me: I want to visit my instructor Mr.xxxx xxxx
3,VO: How much is your monthly income?
  me: #150,568 ($752)

  VO: its not what you can go U.S for, sorry your visa is not approved this time you can reapply, and he gave me one blue card which is 214(b) when i go through the card it was stated that i can reapply any time but some information must change from the old Application form.

Please Sir/Ma, am thinking of reapply soon. Firstly, my question is that, what category visa can i choose? because i want to go and learn more about my job for just two weeks(Short Course) not from a University or College but from a Fire Service Department in U.S. and they have arranged for my visit over there. I wanted to tell the Visa Officer that i want to go and learn more about my job for two weeks, but someone told me that, Learning or Short Course(Training) visa is different from visiting visa, and visiting visa was the one i applied.

Secondly, when i searched, i learned that,if you wish to pursue a course of study which is not principally academic in nature at an established vocational or other recognized nonacademic institution such as a post secondary vocational or business school, you will require an M-1 visa.

Thirdly, concern the Purpose of traveling, can i say, am going for training from a Fire Service Department or am going for two weeks course from a Fire Service Department?

Please assist me with your experiences, i would appreciate your quick response. Thanks.