The correct answer is A) Information about the number of salmon offspring are produced over several years.
The empirical evidence that could most effectively and directly be used to convince lawmakers to remove a dam that is blocking a river used by wild salmon to reach their breeding grounds is "Information about the number of salmon offspring are produced over several years."
When you want to be listened by local authorities about what you consider is a serious issue for the community of the environment, you need to provide valid and serious data, not only your opinion or beliefs. Local authorities are expecting to have the right reasons, valid information, the statistics and the possible consequences of not attending an issue. In this case, an environmental issue. That is the best way to convince them and how this is going to affect them in case they do not attend the problem.
