Select the most appropriate option to fill in the blank. Her legacy endures;…

Concept: When the noun "symbol" introduces the quality, ideal, or cause that something represents, English commonly uses the pattern symbol + "of" + noun phrase, as in "a symbol of hope" or "a symbol of courage". The intended relation and the complement together identify this construction; other prepositions can occur with "symbol" when the relation changes.

Application: Here, "selfless service" names the ideal represented by the person. The relation is therefore expressed as "symbol of selfless service", giving the completed sentence: "Her legacy endures; she remains an iconic figure and symbol of selfless service."

Contrast: Each remaining preposition expresses a different relation:

• "at" locates something at a point in space or time, as in "at the gate" or "at six o’clock"; that point relation is not the one expressed here.

• "with" introduces accompaniment, an instrument, or an attached feature, as in "tea with sugar" or "cut with a knife"; that accompaniment relation is not the one expressed here.

• "in" places something within a space, period, or state, as in "in the hall" or "in April"; that containment relation is not the one expressed here.

Result: The appropriate preposition is "of", producing "symbol of selfless service".