Answer:
Last option (counting from the top)
Step-by-step explanation:
For a given function f(x), the difference quotient is:

In this case, we have:

Then the difference quotient will be:

Now we should get a common denominator.
We can do that by multiplying and dividing each fraction by the denominator of the other fraction, so we will get:

Now we can simplify that to get:

Then the correct option is the last one (counting from the top)