Much as I admire his courage, I think he’s foolish to do such a thing.

• A. Though I admire him, I think his courage is foolish.
• B. Though I admire his courage, I am a foolish to do such a thing for him.
• C. Although I admire his courage, I think he’s foolish to do such a thing.
• D. Although I admire his courage, he’s a foolish to do such a thing.