The three abundant elements in the earth’s crust are aluminium, oxygen and silicon. The correct order of their abundance is

oxygen, aluminium, silicon
aluminium, silicon, oxygen
oxygen, silicon, aluminium
silicon, oxygen, aluminium

The correct answer is A. oxygen, aluminium, silicon.

Oxygen is the most abundant element in the Earth’s crust, making up about 46.6% of its mass. Silicon is the second most abundant element, making up about 27.7% of the Earth’s crust. Aluminium is the third most abundant element, making up about 8.1% of the Earth’s crust.

The other options are incorrect because they do not list the elements in the correct order of abundance.