Final answer:
The best sentence to replace the underlined one and engage readers is 'Have you ever taken a risk that didn’t work out?' This choice effectively introduces the essay's main idea about learning from risks, drawing attention and encouraging reflection.
Step-by-step explanation:
To best grasp the reader's attention and introduce the main idea in Aiko's essay on learning from taking risks, the most effective replacement for the underlined sentence would be Choice A: Have you ever taken a risk that didn’t work out? This question directly engages the reader and sets the stage for discussing the lessons learned from risks, as exemplified by Frederick Douglass, the Challenger crew, and Phineas Gage. It also reflects the idea that taking risks, whether successful or not, can provide valuable lessons—a main concept in the essay that is about to unfold.
Such a question in an introduction serves a dual purpose: it both piques curiosity and encourages personal reflection, drawing the reader into the narrative while remaining aligned with the essay's theme. The question format is a common strategy for engaging readers, as it prompts them to think about their experiences relative to the topic at hand.