The answer is c hope this helped
The answer is B) Zinc will replace lead (...)
Calcium has electrons in more energy levels than magnesium. The number of electron in calcium atom is 20 which means 4 energy levels. (2 electron in first shell+ 8 electron in second shell+8 electron in third shell+ 2 electron in fourth shell). While number of electron in magnesium atom is 12 which means 3 energy levels. (2 electron in first shell+ 8 electron in second shell+ 2 electron in third shell). Also the Calcium third energy level contains more electron than magnesium.
I think the answer is D
It replaces the element alone with an element next to another element. A+BC ->AC+B