NEET Physics Current Electricity Questions Solved

A wire of radius r has resistance R. If it is stretched to a radius of $\frac{3r}{4}$, its resistance becomes 

(1) $\frac{9R}{16}$

(2) $\frac{16R}{9}$

(3) $\frac{81R}{256}$

(4) $\frac{256R}{81}$