An input is best defined by an input is the value that determines another based on the relation or the function rule, usually the x-values in a set of ordered pairs or on a table or graph. Option D
In mathematical functions or relations, an input refers to the independent variable, typically represented by x-values in ordered pairs.
The input value is used to determine or calculate the corresponding output value, which is the dependent variable or the result of applying the function or relation rule to the input.