Which statement concerning $\alpha$-particles is correct?
- A$\alpha$-particles emitted from a single radioactive isotope have a continuous distribution of energies.
- B$\alpha$-particles have less ionising power than $\beta$-particles.
- CThe charge of an $\alpha$-particle is $+1.60 \times 10^{-19}\,\text{C}$.
- DThe speeds of $\alpha$-particles can be as high as $1.5 \times 10^{7}\,\text{m s}^{-1}$.