Organic Chem Williamson Method?

a) and b) will give mixtures, including dimethyl ether, for example. c) will give elimination because the bromide is secondary. d) will give methyl isobutyl ether, it has one carbon extra. e) will give the best reaction as methyl has the least steric hindrance to an SN2 substitution reaction, it cannot undergo an E2 elimination reaction.