This is a bad question because it's a case of "the closest to 90" as opposed to "do you understand the idea?" The idea is that since bonding uses the p orbitals, which are orthogonal and oriented along the axes, the ligands must be orthogonal to each other. So you should be thinking "90" and if you can get to that point, you understand the idea behind the problem.
s orbital is spherically symmetric, so it will repel electrons in all directions equally and thus not affect the geometry about the metal.