A can do a piece of work in 4 days. B can do it in 5 days. With the assistance of C they completed the work in 2 days. Find in how many days can C alone do it?  Choose the correct option.
A) 22
B) 20
C) 288
D) 277
E) 12
C = 1/2 - 1/4 - 1/5 = 1/20 =&gt; 20 days   Answer: 20
<result>B</result>
A can do a piece of work in 4 days. B can do it in 5 days. With the assistance of C they completed the work in 2 days. Find in how many days can C alone do it?