Question on Nucleophilic Substitution

Out of the two compounds given below which one will undergo nucleophilic substitution faster? Why?

Answer:

There are couple of actors that affect the rate of nucleophilic substitution reactions. Here, the leaving group (halide ion) is the same and hence the electrophilic carbon can affect the rate of the reaction to a greater extent. In (a) the carbon connected to the bromine atom will tend to carry a negative charge because it having a negative charge will make the ring aromatic. In (b) the the carbon connected to the bromine atom will tend to carry a positive charge because it having a negative charge will make the ring aromatic. So, (b) undergoes nucleophilic substitution faster than (a).