Oxidation number of rubidium in $\mathrm{R}{\mathrm{b}}_2\mathrm{O},\mathrm{R}{\mathrm{b}}_2{\mathrm{O}}_2$ and $\mathrm{R}\mathrm{b}{\mathrm{O}}_2$ , can be given respectively, as

• A

  $+1,+4$ and $+2$
• B

  $+2,+1$ and $+\frac{1}{2}$
• Correct answer
  C

  $+1,+1$ and $+1$
• D

  $+1,+2$ and $+4$

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