C. 5
Step-by-step explanation:
The coeff of

Is 15.
So by that we can write 3m = 15
m is 5.
The importance of finding new sources of energy,Are we are running out of resources on our planet. There are so many resources that are reusable. an ones that only have a certain amount of an we are running out of it. so if we find new sources of energy we could save our planet it an stop it from wasting an killing out planet