Gas turbines vs. steam turbines: identify the true comparative statements in power-plant practice. Gas turbine plants are compact and include a compressor and a combustion chamber. Overall (simple-cycle) efficiency is typically lower than that of steam turbine plants under similar conditions. Choose the option that best summarizes these facts.

Concept/Approach
A simple-cycle gas turbine comprises a compressor, combustor, and turbine on one shaft, yielding a compact plant that is lighter and requires less floor space than a comparable steam plant. However, simple-cycle thermal efficiency is generally lower than steam Rankine plants (unless combined-cycle is used).

Why 'all of these' is correct
(1) Less space: high power-to-weight and compact layout.
(2) Compressor + combustor: defining components of gas turbines.
(3) Less efficiency (simple cycle): lower cycle efficiency at moderate TIT and pressure ratios compared to large steam plants.

Final Answer
all of these.