A solution is made by mixing one mole of volatile liquid A with 3 moles of volatile liquid B. The vapour pressure of pure A is 200 mm Hg and that of the solution is 500 mm Hg. The vapour pressure of pure B and the least volatile component of the solution, respectively, are:

A

1400 mm Hg, A

B

1400 mm Hg, B

C

600 mm Hg, B

D

600 mm Hg, A