If $c$ is a real number and $\frac{x^2}{c-12}+\frac{y^2}{7-c}=1$ represents a hyperbola, then

• A

  $7 < c < 12$
• B

  $c < 7$
• C

  $c>12$
• Correct answer
  D

  $c < 7 \text { or } c>12$

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