1. Given data

   • Prism is equilateral, so prism angle: $A = 60^\circ$
   • Refractive index of prism material: $\mu = \sqrt{3}$
   • Light suffers minimum deviation.

2. Condition for minimum deviation For a prism at minimum deviation: $i = e$ and the refraction angles inside the prism are equal: $r_1 = r_2 = \frac{A}{2}$

   Therefore, $r = \frac{60^\circ}{2} = 30^\circ$

3. Apply Snell's law at first face Since light goes from air to prism: $\mu = \frac{\sin i}{\sin r}$

   Substitute values: $\sqrt{3} = \frac{\sin i}{\sin 30^\circ}$

   Using $\sin 30^\circ = \frac{1}{2}$

   we get: $\sqrt{3} = \frac{\sin i}{1/2} = 2\sin i$

   So, $\sin i = \frac{\sqrt{3}}{2}$

4. Find angle of incidence $i = 60^\circ$

5. Check options

   • A: $60^\circ$ ✅
   • B: $45^\circ$ ❌
   • C: $90^\circ$ ❌
   • D: $30^\circ$ ❌

Therefore, the correct answer is: $\boxed{60^\circ}$