Answer:
Explanation:
B. for it to be a proper function, it must pass the vertical line test (meaning, if you were to fill a continuous line between each of the dots, and then drew a string vertical line down at any point along the function, that vertical line cannot intersect with the function line more than once.
A, would fail the vertical line test, C< and D would also fail, as a vertical line would intersect/cross the function line more than once.