Question

I am sending you a text, it is really long and detailed, so I hope you read it very slowly. Which answer identifies an adjective phrase and the word it modifies

Answer 1

The correct answer is - The adjective phrase really long and detailed modifies the word it.
There is only one adjective phrase in this sentence, and it is the phrase 'really long and detailed.' That phrase refers to, or describes, or modifies the pronoun it (which again refers to the word text).
Very slowly is an adverb phrase; hope you read it is a clause, not a phrase; am sending is a verb phrase.