$\cos ^2\left(\frac{7 \pi}{8}\right)+\cos ^2\left(\frac{5 \pi}{8}\right)+\cos ^2\left(\frac{3 \pi}{8}\right)+\cos ^2\left(\frac{\pi}{8}\right)=$

• A

  $\frac{3}{2}$
• B

  $\frac{2}{3}$
• Correct answer
  C

  2
• D

  1

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