A function is shown: f(x) = 4x2 − 1. Choose the equivalent function that best shows the x-intercepts on the graph.

f(x) = (4x + 1)(4x − 1)
f(x) = (2x + 1)(2x − 1)
f(x) = 4(x2 + 1)
f(x) = 2(x2 − 1)