The correct answer is A) Unions benefit those who belong to them.
Kennedy most likely agreed with this statement: "Unions benefit those who belong to them."
Indeed, when he was the President of the United States he signed Executive order 10988, on January 17, 1962. This order benefited all those workers that did not have any kind of protection. This executive order authorized federal workers to collective bargaining in order to regulate working conditions and salaries.