Answer:
C
Step-by-step explanation:
The easiest way to solve this would be to find the difference between the numbers. We can do [tex]-3-(-9)[/tex] to find the difference of [tex]6[/tex]. We can then make sure this is true for the rest of the sequence by adding 6 to each number.
[tex]-9+6=-3[/tex]
[tex]-3+6=3[/tex]
[tex]3+6=9[/tex]
[tex]9+6=15[/tex]
Now that we've verified that this is true, we know the answer is C
