Question

select the quotation from the story that most strongly suggests that the theme is its good to tackle new challenges.
on his wall hung his best paintings: an apple orchard with red fruit bursting with color; a beach under a blue sky; and the ocean sparkling in the summer sun.
it was hard at first, but marcos brushstrokes grew more confident as the morning wore on.

Explanation:

The theme "It's good to tackle new challenges" is about overcoming initial difficulty and gaining confidence. The quotation "It was hard at first, but Marco’s brushstrokes grew more confident as the morning wore on" shows Marco starting with difficulty and then becoming more confident as he tackles the task (painting, likely), which aligns with the theme. The other quotation describes paintings, not the process of tackling a challenge.

Answer:

It was hard at first, but Marco’s brushstrokes grew more confident as the morning wore on.