The statement that best exemplifies a strong persuasive claim is the last one - School communications should be sent electronically to conserve paper. In this sentence, you have your claim that you want to prove, as well as the reason why your claim is correct. The other options are just facts, they are not sentences you would use in order to persuade someone to believe or do something.
Because of this, our critical thinking skills are being enhanced. When we practice causal analysis, we do not only identify what happened, but instead, we are compelled to dig deeper and learn what caused an event to happen.