A uniform rod AB is suspended from a point X, at a variable distance x from A, as shown. To make the rod horizontal, a mass m is suspended from its end A. A set of (m, x) values is recorded. The appropriate variable that give a straight line, when plotted, are:

A

$$m, \frac{1}{x}$$

B

$$m, \frac{1}{x^2}$$

C

$$m, x$$

D

$$m, x^2$$