I’m trying to learn for my Algebra class and I’m stuck. Can you help?

Simplify the expression below. Assume all variables are nonnegative real numbers.
(Hint: Factor the polynomial).

square root of x squared plus 4 x space plus space 4 end root

A. open vertical bar x plus 2 x plus 2 close vertical bar

B. x plus 2 x plus 2

C. open vertical bar x plus 2 close vertical bar

D. x+2