Answer:
The correct option is D.
Step-by-step explanation:
It is given that Keith used the following steps to find the inverse off, but he thinks he made an error.
The correct steps are:
Step 1: 
Reason: Given
Step 2: 
Reason: Change f(x) to y.
Step 3: 
Reason: Switch x and y.
Step 4: 
Reason: Subtract 5 from each side.
Step 5: 
Reason: Divide each side by 7.
Step 6: 
Reason: Change y to g(x).
Step 7: 
Reason: Switch sides of the equation.
In step 4 Keith add 5 but she should have subtracted 5 from each side.
Therefore the correct option is D.