A radioactive source is positioned close to a detector. For 10 minutes, the radiation reaching the detector from the source is recorded while different materials are placed in between the source and the detector. The table shows which material is placed between the source and detector and the radiation detected in counts. Which types of radiation are produced by the source?
- A$\alpha$-particles and $\gamma$-rays
- B$\alpha$-particles only
- C$\beta$-particles and $\gamma$-rays
- D$\beta$-particles only