Which are the most abundant elements present inside the earth's crust?

1. Al, and Fe 

2. Al, and Cu

3. Fe, and Cu

4. Cu, and Ag

HINT: Al and  Fe are most abundant among these.
Explanation:
Among a number of elements which are available in earth crust, the most abundant elements are aluminium and iron.
Aluminium is third most abundant element in earth crust. i.e., 8.3% by weight while iron present in earth crust with 4.2% by weight.
Copper and silver are also found in earth crust but their abundance percentage is low.