lim as x approaches negative infinity

(3x^5 + 6x + - 3) / (8x^4 + 10)

a. Does Not Exist
b. 0
c. -3/8
d. 3/8

I solved this and got negative infinity as the answer, but none of the answers are listed above.
I finally chose Choice C, but my teacher said the correct answer is A?

A is right

a limit of infinity means it does not exist.