Bar Magnet & Magnetic Moment question from NEET 2021

Answer: (b)

1. Triangle of side $a$: perimeter $3a$, so turns $N = 12a/3a = 4$; area $= \dfrac{\sqrt3}{4}a^2$.
2. $M_1 = 4\cdot I\cdot\dfrac{\sqrt3}{4}a^2 = \sqrt3\,Ia^2$
3. Square of side $a$: perimeter $4a$, so $N = 12a/4a = 3$; area $= a^2$.
4. $M_2 = 3Ia^2$
5. So the answer is (b) $\sqrt3\,Ia^2$ and $3Ia^2$.