Foods can be preserved in many ways by slowing or preventing bacterial growth.Which of these methods should be least effective at inhibiting bacterial growth?

A)Refrigeration: slows bacterial metabolism and growth.
B)Closing previously opened containers: prevents more bacteria from entering, and excludes O₂.
C)Pickling: creates a pH at which most bacterial enzymes cannot function.
D)Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells.
E)Irradiation: kills bacteria by mutating their DNA to such an extent that their DNA-repair enzymes are overwhelmed.