In a monoclinic unit cell, the relation of sides

$a \neq b \neq c$ and $\alpha \neq \beta \neq \gamma \neq 90^{\circ}$

$\mathrm{a} \neq \mathrm{b} \neq \mathrm{c}$ and $\beta=\gamma=90^{\circ} \neq \alpha$

$\mathrm{a}=\mathrm{b} \neq \mathrm{c}$ and $\alpha=\beta=\gamma=90^{\circ}$

$a \neq b \neq c$ and $\alpha=\beta=\gamma=90^{\circ}$