Why Is It Important to Repeat Experiments or Test Hypotheses

Why is it important to repeat experiments or test hypotheses in different ways?

A) Because more people will believe the work
B) Because more grant funding will be sent
C) To make sure the predictions hold up in multiple situations
D) Because as long as there is enough data collected, results can be published.
E) Because that's what science students spend their time doing in order to learn.