c)  Incorrect.  CH₄ is a tetrahedral molecule.  Each of the bonds is polarized toward the carbon atom.  Adding together any two bond dipoles
            gives a subtotal sum halfway between them directed toward the central carbon atom.  When the two subtotal sums are added, they will cancel
            each other out (identical forces directed head-to-head) and the molecule is nonpolar.  CH₃Cl is a tetrahedral molecule.  Each of the three C-H
            bonds is polarized toward the carbon atom while the C-Cl bond is polarized toward the chlorine atom.  Adding together two C-H bond
            dipoles gives a subtotal sum halfway between them directed toward the central carbon atom.  Adding together the third C-H bond and the
            C-Cl bond dipoles gives a subtotal sum which won't cancel out the other subtotal sum (since the combination is different) thus the molecule
            is polar.