JEE Main 2022 Physics question

A radar sends an electromagnetic signal of electric field V/m and magnetic field T which strikes a target on line of sight at a distance of 3 km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t = 0 from radar, then after how much time echo will reach to the radar?

• (1) s
• (2) sCorrect
• (3) s
• (4) s