Agent which on addition to a colony inhibits its growth and on removal the colony regrow is

Option 1 A bacteriostatic agent or bacteriostat -biological or chemical agent that stops bacteria from reproducing, while not necessarily killing them otherwise. "Bacteriostatic" means that the agent prevents the growth of bacteria (i.e., it keeps them in the stationary phase of growth), and "bactericidal" means that it kills bacteria. Option 2 Bactericidal: propey by which a biocide is able to kill bacteria. Bactericidal action differs from bacteriostasis only in being irreversible (ie, the "killed" organism can no longer reproduce even after being removed from contact with the agent). Option 3 Antibiotic: A substance that interferes with a paicular step of cellular metabolism; may be either bactericidal or bacteriostatic Option 4 Antiseptic: An agent that destroys or inhibits the growth of microorganisms in or on living tissue or biologic fluids