Explanation

The principal raw materials for ordinary soda-lime glass are silica (sand, the glass-former), sodium carbonate (soda ash, the flux that lowers silica's melting point), limestone, and cullet (recycled glass); borax and alumina are added for special glasses such as borosilicate and aluminosilicate glass. Option A lists silica, sodium carbonate, borax, alumina and cullets, which matches this standard batch composition. Option C wrongly names magnesium carbonate as a main ingredient (calcium carbonate/limestone is the carbonate used), and options B and D include iron oxide and sodium bicarbonate, which are not main glass-making ingredients.