Kate Has Been Having Trouble Sleeping

Kate has been having trouble sleeping.She feels anxious and irritable some days.She was in a rush to get to her class this morning and too busy to grab any kind of breakfast, even her usual coffee.It is now lunch time, and she has developed a strong headache.She does not drink alcohol and drinks plenty of water.What is the most likely culprit of her sudden headache?

A) Kate is suffering from depression.
B) Kate did not eat.
C) Kate did not drink caffeine.
D) Kate is under too much stress.