For a cubic crystal structure which one of the following relations indicating the cell characteristics is correct?

• A

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

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

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

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

Hence, the correct answer is option: 'C'.