The statement that best describes why the steady state theory cannot explain the radiation detected in space is:
"The theory is based on the idea that an explosion did not occur; therefore, evidence of radiation would not be predicted in the theory."
This is because the steady state theory suggests that the universe is eternal and unchanging on a large scale, and thus does not account for the cosmic microwave background radiation, which is a remnant of an initial hot state (like the Big Bang) that the steady state theory does not predict.