Final answer:
CH4 (methane) is the nonpolar molecule among the choices.
Step-by-step explanation:
The nonpolar molecule among the given choices is CH4, which is methane. Methane is a tetrahedral molecule in which all four hydrogen atoms are evenly distributed around the central carbon atom. Since the electronegativity difference between carbon and hydrogen is small, the molecule does not have an uneven distribution of charge and is therefore nonpolar.