The word that is modified by the prepositional phrase in the sentence is:
tired
Explanation:
A preposition is a word that indicates a relationship between other words. Examples of prepositions are: at, in, on, to, for, from, with, through, etc. A prepositional phrase is constituted by a preposition and its object (complement). In the sentence we are analyzing here, the preposition is "from". Therefore, the prepositional phrase is "from a long day at work". This phrase modifies the word "tired" by giving additional information as to why Taylor's mother was tired.
