In one day, John Smith, a professional assassin, can blow up two buildings or kill five bad guys. His partner Jane can blow up four buildings or kill six bad guys in one day. John and Jane can gain from specialization and trade if Jane______ and John______ . 

a. Kills bad guys; blows up buildings

b. Kills bad guys; kills bad guys

c. Blows up buildings; kills bad guys 

d. Blows up buildings; blows up buildings 

e. None of the above, Jane should do everything since she is better at being an assassin than John is.