How are elements related to the Earth's crust?

The Earth's crust comprises about 95% igneous and metamorphic rocks, 4% shale, 0.75% sandstone, and 0.25% limestone. Oxygen, silicon, aluminum, and iron account for 88.1% of the mass of the Earth's crust, while another 90 elements make up the remaining 11.9%.

The answer is c i think

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