Answer:
The correct answer is a. really difficult
Explanation:
Easy as pie is an expression that we use when we want to say that something is very easy to do. In this case the protagonist doesn't believe that configuring software is easy. On the contrary, he finds difficult.
That is why A is the correct answer, and not B.
C is also wrong option because we use term really delicious when some food or something similar is tasty.
