Select the option that can be used as a one-word substitute for the given…

One-word substitution items ask you to replace a descriptive phrase with the single English word that carries exactly the same meaning; solving them means matching the CORE idea of the phrase — here, WHO benefits and WHAT motivates the person — to the word's root sense, not just a surface keyword.

The phrase describes a person who works for the welfare of others and takes no personal benefit from it. This selfless concern for others' good is called altruism (from the Latin alter, "other"), and a person who practises it is an Altruist — the exact one-word substitute for the given phrase.

Checking the remaining options by their own meaning confirms none of them fits the phrase:

• Egoist — a person whose actions are driven mainly by self-interest and personal advantage.

• Hedonist — a person who treats pleasure and sensory enjoyment as the chief guide of life.

• Idealist — a person guided by high principles or a vision of how things should be, which does not by itself require selfless service to others.