1.
describes what happened first, second, third, and so on.

comparison-and-contrast order

chronological order

cause-and-effect order

order of importance

Chronological Order

Explanation:

A paragraph in chronological order would tell events in order.

Example: If a person was writing about the World Wars, he would start off with WWI before moving on to WWII.

Order of importance can do this, but sometimes, because an ending event would be more important than a beginning event, it would be out or order.

a.) it provides a clue to solve the mystery.

the second option.is correct