Final answer:
The quotation from the story that most strongly suggests that the theme is Goals can be achieved through persistence and preparation is option c) "She ran at least three times a week—sometimes more—and kept increasing her distance and improving her pace."
Step-by-step explanation:
The quotation from the story that most strongly suggests that the theme is Goals can be achieved through persistence and preparation is option c) "She ran at least three times a week—sometimes more—and kept increasing her distance and improving her pace." This quote shows that Joanna is setting goals for herself, persistently working towards them by running regularly and improving her performance.