Prokaryotic Gene Expression and Regulation

Bacterial strategies to evade natural or human-imposed antibiotics are varied and include membrane-bound efflux pumps that export antibiotics from the cell.
A review of efflux pumps states that, because energy is required to drive the pumps, activating them in the absence of the antibiotic has a selective disadvantage. The review also states that a given antibiotic may play a role in the regulation of efflux by interacting with either an activator protein or a repressor protein, depending on the system involved.

Select all types of regulation that are consistent with the information provided.
  negative inducible
  negative repressible
  positive inducible
  positive repressible