Tax return for F1 (Research Assistant)/ F1 (OPT)/ H1b/ Married - dual status alien?

[cjs87]

I'm in a complicated situation with my 2015 tax return. Need your advice.

- From Jan to mid Aug, I worked on F1 for university as a research assistant
- From mid Aug to Sep end, I worked on F1 (OPT) for employer_1
- From Oct to Dec end, I worked on H1b for employer_1...