Letter-sound correspondence is instrumental when learning how to:automatically recognize sight words improve vocalization skills improve comprehension of high-frequency words decode and spell unknown words

The correct answer is "decode and spell unknown words".

The alphabetic principle consists of 2 elements:

Alphabetic understanding, which states that words are composed of letters and each represents a particular sound. Phonological recording, or the relationship between letters and phonemes (letter-sound correspondences).

Whenever an individual sees an unknown word, it will recur to initially detect the letters contained in the word and subsequently relate them to a previously known sound.