Prove that the arc length for the line y = mx + c on the interval [a,b] is _______.

a) (√(b-a)² + (m(b²+c²)-ma²)²)
b) (1/2|b² - a²| + 1/2|m(b² + c²) - ma²|)
c) (∫ₐᵇ √1 + m² ,dx)
d) (mc√b-a)