We can Notice from the Diagram that the Ladder with Wall Forms a Right Angled Triangle.
We know that In A Right Angles Triangle :
(Hypotenuse)² = (First Leg)² + (Second Leg)²
Here the Hypotenuse is the Length of Ladder and One of the Leg is Length away from the Wall
Substituting the Respective Values, We get :
⇒ 5² + (Second Leg)² = 13²
⇒ 25 + (Second Leg)² = 169
⇒ (Second Leg)² = 169 - 25
⇒ (Second Leg)² = 144
⇒ Second Leg = 12 Feet
⇒ The Ladder reaches a Height of 12 Feet
Option C is the Answer