Question

Event 1 and Event 2 are correlated when ________

Answer 1

The answer is: Event 1 has a connection to Event 2.

A correlation basically implies that there is a connection between two events. The connection may or may not be of a causal nature. What it does specify concretely is that there is a mutual relationship or dependence between those two, or amongst more, events; in other words, this means that there is interdependence between the events in question.  

Answer 2

The answer is D because when something has a connection it is obviously correlated.