Which descriptions correctly describe a $\gamma$-ray and a $\beta$-particle?
- A$\gamma$-ray: high-speed electron; $\beta$-particle: electromagnetic radiation
- B$\gamma$-ray: electromagnetic radiation; $\beta$-particle: helium-4 nucleus
- C$\gamma$-ray: electromagnetic radiation; $\beta$-particle: high-speed electron
- D$\gamma$-ray: high-speed electron; $\beta$-particle: helium-4 nucleus