Step 1: Concept
This is a conditional sentence (First Conditional).
Step 2: Analysis
In a First Conditional sentence, the "if-clause" uses the simple present tense to describe a likely future event paired with "will" in the main clause.
Step 3: Evaluation
- "If he had time" is past tense, which does not match the future "will call."
- "If he has time" (Option c) is simple present, making the sentence a grammatically correct first conditional.
Step 4: Conclusion
Replace "had" with "has" for grammatical correctness.
Final Answer: (c)