Concept:When a number and a noun are joined with a hyphen to form a compound adjective before a noun, the noun is always singular.Explanation:The phrase should act as one adjective describing the committee.Thus, write “a fifty-man committee,” not “fifty-men” or any possessive form.Options A, B, and C wrongly use the plural or possessive form.The only correct singular compound modifier is “fifty-man.”Answer:D. fifty-man