A material 'B' has twice the specific resistance of 'A'. A circular wire made of 'B' has twice the diameter of a wire made of 'A'. Then for the two wires to have the same resistance, the ratio $I_B/I_A$ of their respective lengths must be :

Question

( A ) $2$
( B ) $1$
( C ) $\frac{1}{4}$
( D ) $\frac{1}{2}$