Which of the following is a prepositional phrase? slowly woke up harvest moon under the table tired baby

The prepositional phrase is UNDER THE TABLE.

A prepositional phrase begins with a preposition. It ends with the object of preposition that may be a noun, pronoun, gerund, or clause.

Prepositional phrase may function either as an adjective or an adverb. 
If it is an adjective, it answers the question which one?
If it is an adverb, it answers the questions How? When? Where?

Prepositional phrase: UNDER THE TABLE
preposition : UNDER
object of the preposition, noun : TABLE
function as adverb for it answers the question where? 

First we have to know what a prepositional phrase is. A prepositional phrase is a word that indicates the relationship between many elements in a sentence and is a word that consists of a preposition and its object. Here are some examples: Near the pool, around the world, Out the school.

The prepositional phrase in the sentence slowly woke up harvest moon under the table tired baby is Under the Table.

I hope it helps, Regards.