JEE Main 2021 — Magnetic Effects of Current Question with Solution

A coaxial cable consists of an inner wire of radius $a$ surrounded by an outer shell of inner and outer radii $b$ and $c$ respectively. The inner wire carries an electric current $i_0$ which is distributed uniformly across cross-sectional area. The outer shell carries an equal current in opposite direction and distributed uniformly. What will be the ratio of the magnetic field at a distance $\mathrm{x}$ from the axis when $\left(i\right)$ $\mathrm{x}<\mathrm{a}$ and $\left(ii\right)$ $\mathrm{a}<\mathrm{x}<\mathrm{b}$ ?