Select is a function or is not a function to correctly classify each relation

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a) { (3, 7) , (3, 6) , (5, 4), (4, 7)} is a function or not a function

b) { (1, 5), ( 3, 5), (4, 6), (6, 4) } is a function or not a function

c) { (2, 3), (4, 2) , (4, 6) , (5, 8) } is a function or not a function

d) { ( 0, 4) , (3, 2) , (4, 2) , (6, 5) } is a function or not a function

A function relates an input to an ouput. (remember: an input only can have one ouput)

A)it is not a function;
Becacuse we had an input (3) with two outputs (7) and (6); look at the points (3,7) and (3,6)

B) is a function
Because ir relates an input to one output.

C)it is not a function
Becacuse we had an input (4) with two outputs (2) and (6); look at the points (4,2) and (4,6)

D) it is a function
Because it relates an input to one output