Which one of the following can be used to confirm whether drinking water contains a gamma emitting isotope or not?

1. The question asks how to confirm the presence of a gamma emitting isotope in drinking water. 2. Gamma rays are a form of high-energy electromagnetic radiation emitted by radioactive decay of atomic nuclei (isotopes). 3. A Scintillation counter is a detector specifically designed to measure ionizing radiation, including gamma rays. It works by using a scintillator material that emits light when struck by radiation, and this light is then converted into an electrical signal by a photomultiplier tube. 4. A Microscope is used for viewing very small objects and cannot detect radiation. 5. A Lead plate can be used to shield against gamma rays due to its high density, but it doesn't confirm their presence or measure them. 6. A Spectrophotometer measures the intensity of light as a function of wavelength and is used for chemical analysis, not directly for detecting gamma radiation in this context.