Which of the following statements on flame tests are correct?

1. A$\mathrm{Ca}{}^{2+}$ gives a brick-red, $\mathrm{Sr}{}^{2+}$ a crimson-red and $\mathrm{Ba}{}^{2+}$ an apple-green flame.
2. BCopper(II) chloride moistened with conc. HCl gives a blue-green flame.
3. CThe lilac flame of $\mathrm{K}{}^{+}$ can be masked by traces of $\mathrm{Na}{}^{+}$ unless blue cobalt glass is used.
4. DA salt giving a persistent golden-yellow flame must contain $\mathrm{K}{}^{+}$.