Two Conductors Are Made of the Same Material and Have

Two conductors are made of the same material and have the same length.Conductor A is a solid wire of diameter 1 m.Conductor B is a hollow tube of inside diameter 1 m and outside diameter 2 m.The ratio of their resistance, R_A/R_B, is:

A) 1
B)
C) 2
D) 3
E) 4