A can do a piece of work in 3 hours; B and C together can do it in 2 hours, which A and B together can do it in 2 hours. How long will C alone take to do it? Choose the most appropriate option:
A) 2hours	B) 5hours	C) 6hours	D) 4hours	E) 3hours
A's 1 hour work = 1/3;   (B + C)'s 1 hour work = 1/2;   (A + B)'s 1 hour work = 1/2   (A + B + C)'s 1 hour work = (1/3 + 1/2) = 5/6   C's 1 hour work = (5/6 - 1/2) = 1/3   C alone will take 3 hours to do the work.   Answer:3hours
<result>E</result>
A can do a piece of work in 3 hours; B and C together can do it in 2 hours, which A and B together can do it in 2 hours. How long will C alone take to do it?