To find the function \( g(x) \) based on the transformation "reflecting over the x-axis" of the function \( f(x) = -2x + 1 \), we need to reflect the output of \( f(x) \).
Reflecting a function over the x-axis changes the sign of the function, so we would have:
\[ g(x) = -f(x) = -(-2x + 1) = 2x - 1 \]
Thus, the correct response is:
g(x) = 2x - 1