Which of the following correspondences between a crystal system and its unit cell parameters are correct?

1. ACubic: $a=b=c$, $\alpha =\beta =\gamma =60^{\circ }$
2. BTetragonal: $a=b\ne c$, $\alpha =\beta =\gamma =90^{\circ }$
3. CMonoclinic: $a\ne b\ne c$, $\alpha =\gamma =90^{\circ }$, $\beta \ne 90^{\circ }$
4. DHexagonal: $a=b\ne c$, $\alpha =\beta =90^{\circ }$, $\gamma =120^{\circ }$