An increasing force acts on a metal wire and the wire extends from an initial length l₀ to a new length l. The graph shows the variation of force with length for the wire. The energy required to extend the wire from l₀ to l is E.

The wire then contracts to half its original extension.

What is the work done by the wire as it contracts?

A.     0.25E

B.     0.50E

C.     0.75E

D.     E 

C