Explanation:

- Option 3: Oxygen

- The correct choice.

- Most abundant element in the Earth's crust.

- Makes up nearly 46% of the crust's mass.

- Key component of minerals and rocks.

- Option 2: Silicon

- Second most abundant in the Earth's crust.

- Comprises about 28% of the crust.

- Forms silicate minerals.

- Option 1: Iron

- Third most common element in the crust.

- Represents about 5% by weight.

- Integral to many minerals.

- Option 4: Hydrogen

- Not prolific in the crust.

- Mostly found in water and organic compounds.

Option 3: Oxygen is correct. .