Read the quote from Ray Charles and the first part of an analysis of the quote. Answer the question that follows.
"I was born with music inside me. Music was one of my parts. Like my ribs, my kidneys, my liver, my heart. Like my blood. It was a force already within me when I arrived on the scene. It
was a necessity for me-like food or water."

This quote shows a powerful metaphor for how (blank) music is to the makeup of Ray Charles as a person.

Select the best word that fits the tone, flow, and concept of the excerpt.
O essential
O indispensable
O needy
O prerequisite