Concept:The subject “company” (a collective noun) is singular, so it must take a singular verb.
Explanation:The underlined part (c) uses “have,” which is a plural helping verb.
But the subject “a company of five thousand soldiers” is a singular collective noun.
Collective nouns like “company,” “team,” or “group” are treated as singular when the group acts as one unit.
Here the entire company has marched and moved together, so the verb must be singular: “has.”
Therefore, “have just moved” should be corrected to “has just moved.”
Parts (a) and (b) are correct: “A company of five thousand soldiers” and “having marched tirelessly for over five days” have no errors.
Answer:(c)