A and B together can do a work in7 days. If A alone can do it in 14 days. In how many days can B alone do it?
Choose the most appropriate option:
A) 14 B) 10 C) 21 D) 20 E) 25

Rationale: "a 14 1 / 7 â € “ 1 / 14 = 1 / 14 = > 14"
Answer: A