The correct answer is C) Open cycle. In an open cycle gas turbine, air drawn from the atmosphere passes through the engine only once before being expelled back into the atmosphere. This is in contrast to a closed cycle gas turbine, where the same air is continuously recirculated through the engine. The other options are incorrect because: A) Uni-cycle is not a standard term used to describe gas turbine cycles, B) Closed cycle refers to a different type of gas turbine configuration, and D) Semi-closed cycle describes a hybrid configuration that is not an open cycle.