Identify the word that can be used as both singular and plural: (49th Special BCS)

English has certain nouns with irregular or unchanged plural forms that students must memorize. Cannon — Singular and Plural: The word "cannon" can function as both singular and plural, especially in military contexts. — "One cannon fired." (singular) — "Ten cannon were positioned." (plural — unchanged form) — "Ten cannons were positioned." (also acceptable plural) In formal military usage, "cannon" is the standard plural, similar to how "fish" can be both singular and plural. Analyzing other options: ✗ Light: Plural is "lights" (regular) ✗ Shot: Can be plural too (unchanged), but contextually more limited; "cannon" is the standard answer here ✗ Criterion: Singular; plural is "criteria" — this is a Greek-origin word with irregular plural Other words with unchanged plurals: — Sheep → sheep — Fish → fish (or fishes for species) — Deer → deer — Aircraft → aircraft — Species → species Source: Oxford English Grammar; Fowler's Modern English Usage.