Answer:
The correct answer is C. 4(x^2-2x+1).
To factor the expression 4x^2-8x+4, first factor out the greatest common factor of 4.
4(x^2-2x+1)
The expression inside the parentheses can be factored using the quadratic formula or by recognizing that it is a perfect square trinomial.
(x-1)^2
Therefore, the fully factored expression is:
4(x-1)^2.