D) is the answer. note: BF3 is a strong Lewis acid (electron pair acceptor) that reacts with a Lewis base (electron pair donor). CH3NH2 has a lone pair of electrons at N atom and thus acts as a Lewis base to react with BF3. Solution D) is the answer. note: BF3 is a strong Lewis acid (electron pair acceptor) that reacts with a Lewis base (electron pair donor). CH3NH2 has a lone pair of electrons at N atom and thus acts as a Lewis base to react with BF3..