Hint, I am presuming you have read that hybridization is an hypothetical mixing of orbitals at EACH shell.
A) How many electrons are in the first shell? Are any of these electrons, p-electrons?
B) Are inner electrons part of valence electrons?
C) This could have been confusing as it was meant to understand it to be the electrons of the second shell. Silicon, phosphorous, sulfur, and chlorine can presumably have hybridized electrons.
D) Take C, N, O, and F. Add up the number of valence electrons in stable molecules, CH4, etc. How many electrons.
I am hoping by a process of elimination you can understand which electron/orbitals are being mixed to give hybrid orbitals.