Step 1: Identify T. S. Eliot's time period.
T. S. Eliot was a prominent poet in the 20th century. He is known for works such as *The Waste Land* and *The Love Song of J. Alfred Prufrock*, which are iconic examples of modernist poetry.
Step 2: Analyze each option.
- (A) 20th Century: Correct. T. S. Eliot was a 20th-century poet, a key figure in modernist literature.
- (B) 17th Century: Incorrect. T. S. Eliot lived in the 20th century, not the 17th century.
- (C) 18th Century: Incorrect. T. S. Eliot was not an 18th-century poet.
- (D) 16th Century: Incorrect. Eliot was not from the 16th century.
Step 3: Conclusion.
T. S. Eliot is best known as a 20th-century poet.