Final answer:
The most important sentence to include in the summary is the one that covers both Joey's condition of not being able to recognize faces and his efforts to make his parents understand the situation. Option 2.
Step-by-step explanation:
When summarizing a story about a character's struggles, it is important to convey the central conflict or challenge faced by the protagonist. In this case, Joey's predicament of not being able to recognize faces, often referred to as prosopagnosia, and his attempts to make his parents understand his condition are at the heart of the story.
Therefore, the most important sentence to include in the summary would be the one that encapsulates the main issue and the protagonist's efforts regarding it. Sentence 2) The story is about Joey's struggle to make his parents understand his condition, seems to cover both these aspects effectively.
SO Option 2.