f: [0, ∞) to [0, ∞) defined by f(x) = x/(1+x). The function is:

Correct answer: B. Injective but not surjective

Explanation: f is strictly increasing (injective). But f(x) = x/(1+x) < 1 for all x >= 0, so 1 belongs to codomain but not range. Not surjective.