Concept:Compound adjectives formed with a number and a noun always use the singular form of the noun.
Explanation:When a number is combined with a noun to modify another noun, the modifying noun never takes a plural form.
This is because it acts like one single adjective describing the noun.
For example, we say "a ten-dollar note", not "a ten-dollars note".
Similarly, "committee" is described by the group size, so the correct modifier is "fifty-man".
The phrase means a committee consisting of fifty men, but as a compound adjective, "man" stays singular.
Therefore, "fifty-man committee" is the only grammatically correct option.
Answer:A. fifty-man