Most antibiotics work best on actively growing bacteria. At which phase are bacteria most susceptible to the actions of these antibacterial drugs?

The correct answer is - log phase

Explanation:

Most antibiotics work on actively growing bacteria and the log phase is the phase when bacteria is metabolically most active and actively divide. Bacteria is most susceptible to antibiotics in log phase because the target of most antibiotic is cell wall, protein, DNA and in log phase new proteins, DNA and cell wall is actively synthesized in large amount.

Therefore antibiotics get their target easily during the log phase of bacteria which allows the bacteria to become most sensitive towards antibiotics in this phase. Therefore the right answer is log phase.