Two pieces of copper wire are the same diameter. The length of wire $A$ is twice that of wire B$.$ How do their resistances compare?

$R_A=R_B$

$R_A=\frac{1}{2}{R}_B$

$R_A=\frac{1}{4}{R}_B$

$R_A=2R_B$

$R_A=4R_B$