You are an AI assistant. User will you give you a task. Your goal is to complete the task as faithfully as you can. While performing the task think step-by-step and justify your steps.
system
How does the sentence end?

Jennifer learned to read before they were four but Amy did not until they were ten because 
pick from the following. [i] Jennifer was very slow. [ii] Amy was very slow.
user
To complete the sentence with the appropriate option, I will analyze the context provided:

- Jennifer learned to read before they were four.
- Amy did not learn to read until they were ten.

Based on this context, the sentence should end with:

Jennifer learned to read before they were four but Amy did not until they were ten because [ii] Amy was very slow.
assistant