Which of the following compounds have a nonzero dipole moment?

Question

a) SiBrCl3 b) SO4-2 c) GaH3 d) I2

note: there may be more than one answer
plz help asap

Answer 1

a

On the off chance you want to learn why, Si has four things around it and not all four are the same, so it has a dipole. Everything else is surrounded by identical things, so they're symmetric and has no dipole.

Answer 2

You have to draw the Lewis Structures to figure it out