The Light Element Lithium (Which, on Earth, Is Part of Medications

The light element lithium (which, on Earth, is part of medications that improve the lives of people with mental health illnesses) is more common in cosmic rays than it is in the Sun and the stars. What do astronomers think is the reason for this?

A) there is a lot of lithium (and other light elements) in interstellar dust
B) lithium is so easy to fuse, its fusion happens outside of stars in hot HII regions
C) because cosmic rays move so fast, they can collide with atoms of carbon, nitrogen, and oxygen and break them apart, producing more light elements like lithium
D) lithium is radioactive; its nucleus decays (falls apart) very quickly
E) this is an unsolved problem in astronomy
Section 20.5: The Life Cycle of Cosmic Material