Answer:
Option (3)
Step-by-step explanation:
From the picture attached,
Area of white square = (side)²
Length of each side of the white square = (b - a)
Area of white square = (b - a)²
Area of each right triangle = 
= 
Area of four right triangles = Area of big square - Area of white square
= 
Since area of 4 right triangles = 4(Area of each right triangle)
c² - (b - a)² = ![4[\frac{1}{2}(ab)]](https://tex.z-dn.net/?f=4%5B%5Cfrac%7B1%7D%7B2%7D%28ab%29%5D)
Therefore, Option (3) will be the answer.