Step 1: Understand the comparative structure.
When comparing two things, the correct adjective form is the comparative form, which typically ends in "-er." In this case, we are comparing "he" to another standard, so "older" is the correct form.
Step 2: Analyze each option.
- (A) old: Incorrect. "Old" is a positive form, not a comparative one.
- (B) much old: Incorrect. "Much" is not used with the adjective "old" in this context.
- (C) oldest: Incorrect. "Oldest" is the superlative form, used when comparing three or more things.
- (D) older: Correct. "Older" is the proper comparative form of "old."
Step 3: Conclusion.
The correct sentence is "He looks older than he is."