Final answer:
The only molecular geometry for a nonpolar AX4 molecule is tetrahedral, where the symmetric arrangement of identical atoms around the central atom allows for an even distribution of electrical charges.
Step-by-step explanation:
The only possible molecular geometry for a nonpolar molecule with the formula AX4 is tetrahedral. To be nonpolar, the molecule must have an even distribution of electrical charges, and for AX4, this is achieved when the four identical atoms (X) are symmetrically arranged around the central atom (A). In a tetrahedral geometry, each bond angle is 109.5 degrees, allowing for an even distribution of charge that can lead to a nonpolar molecule, given that the four atoms X are the same. This symmetry means there are no lone pairs on the central atom, and all bond dipoles cancel out.