Subject: mathqa
Question: a and b undertake to do a piece of work for $ 600 . a alone can do it in 6 days while b alone can do it in 8 days . with the help of c , they finish it in 3 days . find the share of a ?
Option: 
A: $ 150
B: $ 100
C: $ 250
D: $ 300
Answer: D