Does this table represent a function ,why or why not?

For this case we have, that by definition, a mathematical function is a relation that exists between two sets, through which, to each element of the starting set is assigned a single element of the arrival set.

The table shows that each element of the first set is assigned a single element of the second set, so we have a function.

Option D

last one.

step-by-step explanation:

last one.

generally speaking, the others follow some sort of pattern that correlates to either linear (looks like a straight line) or sinusoidal (looks like an s).

the last one is just a random cloud of points that doesn't correlate to any particular known order.