Point given in Option C represents a function.
By definition of a function,
"If two points lie on the graph of a function, 'x' values can't have two different 'y' values.
Example: Two coordinates (1, -1) and (1, 4) will not represent a function as x = 1 has two different y values (-1 and 4).
Now check for every option.
Option A
(1, 9) and (1, -4)
Two different y values (9 and -4) for the same value of x = 1.
Therefore, (1, 9) doesn't represent a function.
Option B
(5, 7) and (5, -2)
Two different y values (7 and -2) for the same value of x = 5/
Therefore, (5, 7) doesn't represents a function.
Option C
(3, -4)
Since, y-values of all the points are different for every value of x,
Therefore, it represents a function.
Option D
(0, 8) and (0, 3)
Two different y values (8 and 3) for the same value of x = 0.
Therefore, (0, 8) doesn't represent a function.
Option (C) is the correct option.
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