A simple sentence has only one subject and one ________
a. structure
b. pattern
c. predicate
d. sentence-order

The correct answer is Option B (c only).

Key Points:
• Concept: Definition of a Simple Sentence.
• Explanation: By standard grammatical definition, a Simple Sentence consists of a single independent clause, which contains exactly one subject and one predicate (having a single finite verb). Statement 'c' ('predicate') completes the sentence definition.
• Option Mapping: Statement 'c' is in Option 2 ('c only').
• Official Key: Option 2 ('c only') is the official correct option.
• Key Takeaway: Remember: A Simple Sentence contains exactly one subject and one predicate.