Final answer:
Coalition formation is the tactic of pooling resources and power of a group to influence people outside the group. So, the correct answer is option a.
Step-by-step explanation:
The tactic known as coalition formation refers to attempts to influence people outside a group by pooling the resources and power of its members. In this tactic, different groups come together to achieve a common goal by combining their efforts and resources. For example, multiple environmental organizations might form a coalition to advocate for stronger regulations on pollution.
So, the correct answer is option a.