W-4 : If you are a single F-1 with OPT with no dependents, you will only want to claim 1 exemption on your W-4. Just claim yourself (box A) and put "1" for Box #5.
NC4-NEZ : Just check the "single" box and put "0" in box 1 (if you are single with no dependents you can not claim head of household)
