Which of the following is an even function

Answer:
f(x) = |x|
Step-by-step explanation:
function is even if and only if f(-x) = f(x)
f(x) = |x| ; regard to its sign f(x) = x
f(-x) = |-x| ; regard to its sign f(-x) = x
So answer is f(x) = |x| is the even function