Which one of the following relationships is correct for cubic (C) and rhombohedral (R) unit cells ?

Options

A. `C a ne b ne c, alpha=beta=gamma `
`R:a=b=c,alpha=beta=gamma=90^(@)`
B. `C a = b = c, alpha ne beta ne gamma `
`R:a ne b ne c,alpha=beta=gamma=90^(@)`
C. `C a = b = c, alpha=beta=gamma `
`R:a=b ne c,alpha= beta=gamma=90^(@)`
D. `C a = b = c, alpha=beta=gamma `
`R:a=b ne c,alpha= beta=gamma ne 90^(@)`

Answer

D