Please explain the reason behind the answer as well, thanks!
Solution
Since bromine atoms are attached to primary carbon atoms, SN2 reaction will occur rapidly.
Also, since 1 equivalent of strong nucleophile (OH−) is added, 1 Br atom will be substituted which is less sterically hindered.

Hence, the correct answer is option (b).
Since bromine atoms are attached to primary carbon atoms, SN2 reaction will occur rapidly.
Also, since 1 equivalent of strong nucleophile (OH−) is added, 1 Br atom will be substituted which is less sterically hindered.

Hence, the correct answer is option (b).