Which option best defines on behalf?

• A. Representing
• B. In the interest of
• C. On part of
• D. Supporting

Answer: (A)

The main idea is acting as a representative for someone else. When you do something on behalf of another person, you are doing it in their name or with their authority, representing their interests. That’s why “representing” is the best fit. For example, a spokesperson speaks on behalf of the company, acting as its representative.

The other options miss this agentive sense: “in the interest of” describes motivation or benefit, not who acts; “on part of” isn’t a standard expression in this context; “supporting” means backing or helping, not necessarily acting as the person’s agent or representative.