WHERE IS THE MATH PROBLEM
Answer:

Option D is correct option.
Step-by-step explanation:
We are given: 
We need to find f(x+h)
For finding f(x+h) we need to replace x by x+h

Finding f(x+h) we get:

Option D is correct option.
Multiply exponents together if it is on another exponent
(8^2)^6= 8^12