In a bicycle the radius of rear wheel is twice the radius of  front wheel. If ${\mathrm{v}}_{\mathrm{F}} \mathrm{and} {\mathrm{v}}_{\mathrm{r}}$ are the speeds of top most points of front and rear wheels respectively, then

• A

  ${\mathrm{v}}_{\mathrm{r}} = 2{\mathrm{v}}_{\mathrm{F}}$

• B

  ${\mathrm{v}}_{\mathrm{F}} = 2{\mathrm{v}}_{\mathrm{r}}$

• C

  ${\mathrm{v}}_{\mathrm{F}} = {\mathrm{v}}_{\mathrm{r}}$

• D

  ${\mathrm{v}}_{\mathrm{F}} > {\mathrm{v}}_{\mathrm{r}}$