Which physical characteristic is shared by both Mr. Benedict and Mr. Curtain?

The correct answer highlights the specific details of Mr. Benedict and Mr. Curtain's appearances in the story. Both characters are noted for their distinctive fashion sense, often characterized by their use of green plaid suits. This characteristic sets them apart and serves as a visual representation of their contrasting personalities.

The choice related to blue suits does not reflect what the characters wear; instead, it is the green plaid that is emblematic of their identities in the narrative. While it is mentioned that Mr. Benedict and Mr. Curtain each have their own unique traits, the reference to physical disabilities is more applicable to the overall characterization rather than a shared trait. The detailing of long hair does not apply to both individuals. Therefore, the acknowledgment of their matching green plaid suits effectively highlights a key similarity between Mr. Benedict and Mr. Curtain in the context of their descriptions and overall character design in the story.