The following graph represents the variation of (1/v) with (1/u) of a spherical mirror. Which of the following is correct?

By using mirror equation, u is object distance, v is image distance.

$\frac{1}{\mathrm{f}}=\frac{1}{\mathrm{u}}+\frac{1}{\mathrm{v}}$

$\frac{1}{\mathrm{v}}=\frac{1}{\mathrm{f}}-\frac{1}{\mathrm{u}}$

$\mathrm{y}=\mathrm{c}-\mathrm{x}$  ; where, $\mathrm{c}=\frac{1}{\mathrm{f}}=\mathrm{intercept} \mathrm{of} \mathrm{the} \mathrm{graph}$

Since, intercept is negative, so f will be negative.

Hence, it is a concave mirror.

For point A: 

u is negative and v is positive. So, image is virtual and magnified.

For point B: 

u is +ve while v is -ve, so, it can be for virtual object and real image.

For point C:

u and v both are negative and equal to f/2 . It represents real image and real object of same size. It will be inverted.