20. The term used to describe a gas turbine in which the turbine exhaust passes through a cooler and back to the compressor inlet is which of the following?

A closed-cycle gas turbine recirculates the working gas, directing turbine exhaust through a cooler before returning it to the compressor inlet. This distinguishes it from an open-cycle system, which vents exhaust to the atmosphere, and eliminates the non-standard terms 'uni-cycle' and 'twin cycle.'