<span>D. belief in states rights
</span>
Answer: Experiment
Explanation: Scientific research embarked upon in other to test prediction or hypothesis is simply called an Experiment. Experiments are usually carried out in a controlled environment in other to control for external influences or manipulators. It may involve splitting subjects into groups, one is based on the hypothesis to test or validate and the other will be the opposite. The researchers in the context above, intends to validate or test an hypothesis about whether incentives would boost donation. The first group were given incentives while the other group weren't. Which turns out that incentives does boost donation.
Answer:
Donald Trump
Explanation:
Because he is the president of the united states.