How does the author of "Learning Guitar" mostly reveal the character of Holly’s mother?
A. through her interactions with other characters
We see Holly's mother interacting 1. with her daughter 2. with her husband.
1. “You can quit now,” her mom said. “But if you do, it’ll be harder to start back up again. I think you have a decision to make.”
This shows that Holly's mother is supportive of her daughter and tries to encourage her to continue learning how to play the guitar. She also wants her daughter to show maturity and make the right decision herself.
2. “Since when did you know what a G or a D should sound like?” Holly's mom asked.
This question shows that Holly's mom is very perceptive, and she certainly understands that her husband complimented their daughter on her guitar skills simply to make Holly feel good and motivate her (Holly) to keep practicing.
As for Holly’s mother's actions, we have only this:
"Holly's mom was in the kitchen baking a pie and listening to her daughter's struggles. She took the pie out of the oven and placed it on the counter."
From the given excerpt, we can only say that she can bake and she follows her daughter's progress, slow as it may be, with this guitar practice. Not very much really. So the answer is A.