Here's why:
* Personification is giving human qualities or characteristics to inanimate objects or abstract concepts. In this case, "humour" is a concept, and it's being described as "cold and drowsy," which are qualities typically associated with people.
Let's break down why the other options are incorrect:
* Simile: A simile uses "like" or "as" to compare two things. This phrase doesn't use those words.
* Allusion: An allusion is a reference to something outside the text, like a historical event, a famous work, or a myth. This phrase doesn't make such a reference.
* Flashback: A flashback is a shift in time within a narrative, going back to an earlier event. This phrase doesn't describe a change in time.