Identify an Antiderivative Function

HELP
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On the left is a graph of a function `f`, and one of the three graphs on the right is an antiderivative of `f`. Make a guess and check your answer by clicking the red question mark buttons. Give yourself a new, randomized problem by clicking the "Reset Graphs" button. (By the way, why do we write an antiderivative of `f` instead of the antiderivative of `f`?)