H4 to F1 COS,F1 visa approved at hyderabad

I have changed my status from h4 to f1 in usa .From first semester, i was on F1 without stamp.I completed 4 semesters ,9 out of 10 courses were completed then i went for visa stamping at hyderabad consulate on 22nd May, 2015.I was little tensed because interviewer has been rejecting visas for everyone. Person before me was asked technical questions related to Electronics . Then my turn came and here it goes….

VO: hello mam
ME: Good morning, sir.
VO: How many universities did you apply?
ME: i have applied for 4
VO:Where does your husband live?
ME:He lives in XXXXXXXX city
VO: where does your husband works?
ME: He works for XXXXXX corporation.
VO:Whats your husband salary?
ME: 120K
VO: Does your husband sponsoring for your education?
ME: Yes
VO:How many semesters did you complete?
ME: 4
VO:Why did you come for F1 stamping?
ME: i have family emergency and i was supposed travel outside USA.
VO: You can study on H4.Whats need for F1?
ME: In my university, our professor is offering research assistantship and i want to utilize it
VO: So now you are going to work on OPT? Say yes or no?
ME: NO, if its an proper offer i would work
VO: Your Visa is approved mam
VO: (vo with smiling face) i know mam you will be working on OPT. Don't lie.
VO: Your Visa is approved mam
ME: Thank you

What i observed is not to lie .