Consider the function represented by the following table.

Exponentially

Step-by-step explanation:

If the data is linear, the first differences will be the same.  These are the differences in y-values:

6-3 = 3; 12-6 = 6; 24-12 = 12.  These are not the same, so the data is not linear.

If the data is quadratic, the second differences will be the same.  These are the differences in the first differences:

6-3 = 3; 12-6 = 6.  These are not the same, so the data is not quadratic.

This data forms a geometric sequence, as each term is multiplied by 2.  Geometric sequences can be written as exponential functions, so this is an exponential data set.