Which of the Following Is a Definition of a Trade/labor

Which of the following is a definition of a trade/labor union?

A) A group of workers joined together in a specific type of organization for the purpose of improving their working conditions as well as to help in promoting the common interests of the group.
B) An association of employees formed to improve their incomes and working conditions by collective bar- gaining with the employer or employer organizations.
C) An organization of wage earners or salaried employees for mutual aid and protection and for dealing col- lectively with employers; trade union.
D) All of the above