What is the sum of the focal distances of a point of an ellipse $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$ ?

• A

  $a$
• B

  $b$
• Correct answer
  C

  $2 a$
• D

  $2 b$

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