Which of the following BEST describes Nigeria's labor unions?

a. Although ethnic, regional, and religious differences have hampered their solidarity, they have served as an important challenge to the government and a potent force in society.
b. They are extremely corrupt and have colluded with the federal government for rents.
c. Due to a history of state corporatism, they have been co-opted by the government and fail to act independently.
d. They have never been a significant force in Nigeria.
e. Because they are highly fragmented along ethnic, regional and religious differences, their political impact has been minimal.

a