If an object is placed between two mirrors held perpendicular to each other. Then number of images formed is

The correct option is A $3$

$n=\frac{{360}^{\circ }}{\theta }-1$
No. of images formed by plane mirror inclined to each other at angle $\theta$ is given by formula
Angle between Plane mirrors is $\theta ={90}^{\circ }$
No. of images $n=\left(\frac{{360}^{\circ }}{{90}^{\circ }}\right)-1=4-1=3$