Select the most appropriate option to fill in the blank.

Keats and Shelly were poets of the same period; in other words, they were __________.

The correct answer is contemporaries.

Step-by-step Explanation:

1. The sentence states: "Keats and Shelly were poets of the same period; in other words, they were __________."

2. We need to find a word that means "living, occurring, or existing at the same time" or "belonging to the same period."

3. Let's analyze the definitions of the given options:
- contemporaries: People living or existing at the same time. This directly fits the context of being "poets of the same period."
- co-writers: People who write something together. Keats and Shelley did not write their poems together, so this is incorrect.
- colleagues: People who work with each other, especially in a profession or business. While both were poets, they did not work together in an office or organized professional setting.
- associates: Partners or companions in business or at work. This implies a direct business or personal connection, whereas "contemporaries" specifically refers to sharing the same time period.

4. Therefore, "contemporaries" is the most appropriate word to fill in the blank.