Identify which of the following graphs represents a non-linear function?

The graph that is not a straight line represents a non-linear function.

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?

Hello!
volume of sphere =4/3.pi.r^3