Using the indicated substitution, evaluate the integral of (2x)/(√(x²+8))dx. Which of the following options correctly represents the value of the integral?

A) ∫(2x)/(√(x²+8))dx, where u = x² + 8
B) ∫(2x)/(√(u))dx, where u = x² + 8
C) ∫(2x)/(√(x²+8))du, where u = x² + 8
D) ∫(2x)/(√(u))du, where u = x² + 8