Correct Answer:
B. People help each other mutually
The idiom 'One hand washes the other' signifies a relationship of mutual benefit or reciprocity. It means that if one person helps another, the favor will likely be returned, creating a cycle of assistance. Just as one hand cannot effectively clean itself without the aid of the other, people often require cooperation to achieve their goals. Option B, "People help each other mutually," perfectly captures this essence. Distractors like "To clean oneself" are literal interpretations, while "To steal something" and "To work alone" contradict the core meaning of cooperation and shared benefit inherent in the idiom.