Answer:
C. -9x-3
Explanation:
Use distribuitve property.
DISTRIBUTIVE PROPERTY
A(B+C)=AB+AC
A(B-C)=AB-AC
-3x-6x-8+5 ← (Group like terms & combine like terms.)
-3x-6x=-9x ← (Add and subtract elements to the numbers from left to right.)
-9x-8+5
-9x-8+5 ← (Solve & simplify)
-8+5 ← (Add & subtract.)
-8+5=-3
= -9x-3

Therefore, the correct answer is (C.) -9x-3.