Two wires are made of the same material and have the same volume. The first wire has cross-sectional area A and the second wire has cross-sectional area 3A. If the length ofthe first wire is increased by $$\delta $$ l on applying a force F, how much force is needed to stretch the second wire by the same amount ?

A

F

B

4 F

C

6 F

D

9 F