Escape Velocity $v_e=\sqrt {\large\frac{2GM_e}{R_e}}$

$\qquad= \sqrt {\large\frac{2G \bigg(\Large\frac{4}{3} \large \pi \rho R_e^3d\bigg)}{R_e}}$

$\qquad=\sqrt {2G \bigg(\large\frac{4}{3} \normalsize \pi \rho R_e^2\bigg)d}$ => $v_e \alpha R$

Since density is same.

When radius is doubled escape velocity gets doubled

$2v_e=2 \times 11 =22 \;km/s$

Hence a is the correct answer.