Option 1 -> Allegory is a narrative where characters/events symbolize broader ideas; this phrase is not symbolic storytelling.
Option 2 -> Simile makes comparisons using "like" or "as"; the phrase contains no such comparison words.
Option 3 -> Alliteration is repetition of initial consonant sounds; "sky blushed" lacks this sound pattern.
Option 4 -> Personification gives human qualities to non-human things; "blushed" is a human action attributed to the sky.
Hence, Option 4: Personification -> The sky is given the human ability to "blush," which describes both the color change and evokes an emotional quality, making the description more vivid and relatable -> correct