The observer O can see through a small orifice on the side of a container (radius 15 cm) at a point situated at a height of 15 cm from the bottom, as shown in the given figure. The orifice is at a height of 45 cm. When the container is filled with a liquid up to a height of 30 cm, the same observer can see the bottom of the container. If the refractive index of liquid is x/50, where x is an integer, then the value of x is 15 cm
A. 79
B. 75
C. 86
D. 158
Please explain as it is the ques of nso 2023​