A and B invests Rs.2000 and Rs.4000 respectively in a business. If A doubles his capital after 6 months. In what ratio should A and B divide that year's profit?  Choose the correct choice from the following options:  A) 3 : 5  B) 3 : 4  C) 9 : 2  D) 9 : 9  E) 3 : 1

Rationale: "( 2 * 6 + 4 * 6 ) : ( 4 * 12 ) 36 : 48 = > 3 : 4 answer : b"
Answer: B