In the case of solid, number of degrees of freedom is:
A. 3
B. 5
C. 6
D. 7

Hint: The degree of freedom is defined as a body or molecule that can move freely with or without applying any force in different directions (like x, y, and z axis or directions). The solid is the matter that contains molecules that are packed closely in it, as there are molecules in solids, and then will move in different directions according to the body, so it has the degree of freedom.

Complete step by step answer:
The solid consists of three axes, x-axis, y-axis, and z-axis, it is also called 3-Dimensional. So each axis represents each movement, it means if a molecule is said to move in only x-axis then the degree of movement is 1.
If the molecule is said to move in x-axis and y-axis then the degree of freedom of the molecule is 2.
Like so, a solid consists of 3 axis and each axis consists of 2 movements, then the degree of freedom can be 3 $\times$ 2 = 6.
So in case of solids, the degree of freedom of any body or molecule is 6.
Therefore, the number of degrees of freedom in solids is 6 it means the option (C) is correct.

So, the correct answer is “Option A”.

Note:
We may be mistaken to find the number of degrees of freedom because there are only 3 axes or directions then we may think that the 3 will be the degree of freedom of the solids but we have to be aware that there are still 2 more movements in each axis so the total movements will be 6.