Which of the following can be added to an adjective to create an adjective phrase?

The correct answer is: B & C

Adjective phrases give more information about or modify the noun in a sentence, so adding a noun to an adjective does not create an adjective phrase. Thus options a and d are eliminated. Let us take the sentence "Mary is very tall." Here, 'very' is the adverb added to the adjective 'tall' to make the adjective phrase 'very tall'. Thus option b is possible. Let us take the sentence "This blue shirt is older than that one." Here, 'This' is the determiner added to the adjective 'blue' making the adjective phrase 'This blue shirt'. Therefore option c too, is possible. Thus the correct answer is option e.