$\frac{\cos 15^{\circ} \cos ^2 22 \frac{1}{2}^{\circ}-\sin 75^{\circ} \sin ^2 52 \frac{1}{2}^{\circ}}{\cos ^2 15^{\circ}-\cos ^2 75^{\circ}}=$

• A

  $1$
• B

  $\frac{1}{2}$
• Correct answer
  C

  $\frac{1}{4}$
• D

  $\frac{1}{8}$

Hence, the correct answer is option: 'C'.