Why Do Interest Groups Sometimes Form Coalitions to Work for the Same

Why do interest groups sometimes form coalitions to work for the same policy goal?

A) Policy makers are more likely to respond to large coalitions with a diverse membership.
B) The president responds to coalitions and can then put pressure on Congress.
C) Coalitions of groups can often make up a majority of Americans and create pressure through elections.
D) Coalitions allow groups to exploit loopholes in campaign finance laws.