How many letters does the top answer for “composer of unchained melody” have?

The most common answer is north (5 letters).

Crossword clue: composer of unchained melody

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

north 5 letters wd-fact-v3

the region of the United States lying to the north of the Mason-Dixon line

a composer or singer of melodies. 50% similar → melodist