11 different biology books and 8 different chemistry books lie on a shelf. In how many ways can a student pick 2 books of each type?
Choose the most appropriate option:  A) 80  B) 160  C) 720  D) 1100  E) 1540

Rationale: "no . of ways of picking 2 biology books ( from 11 books ) = 11 c 2 = ( 11 * 10 ) / 2 = 55 no . of ways of picking 2 chemistry books ( from 8 books ) = 8 c 2 = ( 8 * 7 ) / 2 = 28 total ways of picking 2 books of each type = 55 * 28 = 1540 ( option e )"
Answer: E