Question

the root chron means time. what does the word chronic mean?
happening in a way that is difficult to believe
happening in an official or formal way
happening in a vexing or disturbing way
happening frequently or for a long duration

Explanation:

The root "chron" means time. "Chronic" refers to something that occurs frequently or over a long - term period as it relates to the concept of time.

Answer:

happening frequently or for a long duration