Answer:
Option C - She did not divide 28 by 4.
Explanation:
Given : Maya solved an equation incorrectly, as shown below:
Step 1:

Step 2:

Step 3:

To find : Which statement best explains why Step 2 is incorrect in Maya's solution?
Solution :
First we solve the expression again to find the mistake.
Step 1:

Step 2:

Step 3:

Thus, by the above steps it is clear that she did not divide 28 by 4 in step 2.
Therefore, Option C is correct.
The required statement that best explains her mistake in steps 2 is She did not divide 28 by 4.