c. With a bald spot in the middle of my hair— /[They will say: “How his hair is growing thin!”]
In option C, the speaker shows that he is concerned about the opinions of others. He talks about his bald spot and thinks about what people will say about him. Option A shows that he is paying attention to his appearance but it doesn't clearly indicate that it is because he thinks of others' opinions. Option B and D don't really work at all.