Translate the Stated Rule or Relationship to a Formula $c$ , of a Right Triangle Is Equal to the Sum

Translate the stated rule or relationship to a formula.
-The square of the hypotenuse, $c$ , of a right triangle is equal to the sum of the squares of the legs, a and $b$ .

A) $c=a+b$
B) $c=a^{2} b^{2}$
C) $c^{2}=(a+b) ^{2}$
D) $c^{2}=a^{2}+b^{2}$