Answer
The answer is below.
Work Step by Step
We see that both b) and c) have a larger boiling point than Benzene, for the extra atom makes the molecules more polar and increases the london dispersion forces. Because Bromine is larger than Chlorine, the addition of Bromine leads to a larger increase in boiling point than the addition of Chlorine. We see that the last option allows for hydrogen bonding, giving it the largest boiling point.
