Which statement concerning $\alpha$-particles and $\gamma$-rays is correct?
- A$\alpha$-particles are a form of electromagnetic radiation.
- B$\alpha$-particles penetrate materials more easily than $\gamma$-rays.
- CThe emission of an $\alpha$-particle produces a nucleus of a different element.
- D$\gamma$-rays are more ionising than $\alpha$-particles.