Which of the following sentences contains a plural spelling error?
B. Several man helped to lift and move the refrigerator.
It should be: Several men helped to lift and move the refrigerator.
Sentence B doesn't have a matching noun with its modifier because the word "several" is an adjective of number, which indicates the noun should be plural: "men".
The sentence written in a singular form would have been: A man helped to lift and move the refrigerator.