The answer option which is not a region of the Sun is: A. deuterium nucleus.
What is Sun?
Sun can be defined as a medium-sized, main-sequence (yellow dwarf) star that is located at the center of the solar system and it supplies the heat energy and light that sustains life on planet Earth.
According to astronomical information and records, the Sun is marked to be the brightest, largest, and most massive celestial object within the solar system and it comprises the following regions:
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