What would Hippocrates the Father of Medicine say about someone who is moody and generally mildly depressed The person is being influenced by A phlegm B blood C yellow bile D black bile?

The person is being influenced by black bile, one of the 4 humors or temperaments.

Hippocrates only had observations upon which to base his theories. All of 4 humors, as given in the question, were about what he observed about blood exposed to the air.