The total number of ways to answer the question = 4c1 + 4c2+ 4c3 + 4c4 = 24 - 1 =15.
P(getting marks) = P( correct answer in I chance) + P(correct answer in II chance) + P(correct answer in III chance)
= 1/15 + (14/15.1/14) + (14/15.13/14.1/13)
= 3/15 = 1/5