Question

Which is an example of collective bargaining?
workers trying to achieve a better price for the goods they produce
employers joining together to support a particular industry
union leaders negotiating on behalf of a group of workers
unions trying to persuade employers to hire more workers

Answer 1

I think the answer is union leaders negotiating on behalf of a group of workers. 

Answer 2

The correct answer is
unions trying to persuade employers to hire more workers

Collective bargaining is when groups like unions want something form the companies, usually in the form of improving their quality of life on the job. Hiring more workers could mean that they need help an can't achieve everything and need help.