Mathematics

Problem

Which of the following expressions equals

\dfrac{d}{dx}[p(x)q(x)r(x)]

where

p,\,q,

and

r

are differentiable functions? a)

[p'(x)+q'(x)+r'(x)]p(x)q(x)r(x)

p'(x)q(x)r(x)+p(x)q'(x)r(x)

p'(x)q(x)r(x)+p(x)q'(x)r(x)+p(x)q(x)r'(x)

p'(x)q'(x)r(x)+p(x)q'(x)r'(x)+p'(x)q(x)r'(x)