Concept:The most abundant element in the Earth’s crust is the one that makes up nearly half of its mass.Explanation:Oxygen (O) is the most abundant element in the Earth’s crust.It makes up about 46.6% of the crust by mass.This is almost half of the total mass of the crust.Oxygen occurs mainly in compounds such as silicates and oxides.Among the options, oxygen is more abundant than nitrogen, hydrogen, or fluorine.Therefore, the correct option is C.Answer:C. Oxygen