IMAT 2015 Q17 [Fence Rails]

A farmer wishes to fix fencing rails to posts which are already in place. The posts are shown in the diagram. The farmer has a supply of rails, each one 2.4 m long. One rail or part of a rail is to be fixed between each pair of posts. (He can cut the rails into smaller lengths.)


What is the smallest number of rails that he could use?

A. 5
B. 3
C. 4
D. 6
E. 7