Which option most correctly describes the chemical composition of the core?

Correct answer: Iron and nickel

The direct answer is B: the core is mainly composed of iron and nickel. Earth’s core is the deepest major internal layer. On the basis of composition, it is traditionally called NIFE, from Ni for nickel and Fe for iron. The outer core is liquid and the inner core is solid because of the enormous pressure, but both are mainly metallic and rich in iron, with nickel and smaller amounts of other elements. Option A is wrong because silica and alumina are associated with SIAL and the lighter continental crust, not the main composition of the core. Option B is correct because iron and nickel are the standard school-level chemical description of the core. Option C is wrong because oxygen and hydrogen are not the accepted main metallic composition of the core. Option D is wrong because ice and salt describe neither the hot, dense metallic core nor its physical conditions. The reasoning is: identify the deepest layer, recall the traditional term NIFE, expand it as nickel plus iron, and choose B. Memory cue: NIFE = Ni + Fe, so core = nickel and iron.