Which of these metals can displace all the other three metals from their salt solutions?
(a) copper
(b) iron
(c) silver
(d) zinc

(d) zinc
Zinc is more reactive than the other three metals; therefore, it can replace these metals from their salt solutions. In the reactivity series, iron, copper and silver are placed below zinc. Thus, they are less reactive than zinc and are displaced by it from their salt solutions.