Two particles A and B are moving on two concentric circles of radii R1 and R2 with equal angular speed ω. At t = 0, their positions and direction of motion are shown in the figure The relative velocity vA – vB vat \(t = \frac{{\rm{\pi }}}{{2{\rm{\omega }}}}\) is given by

• A. \({\rm{\;\omega }}\left( {{{\rm{R}}_1} + {{\rm{R}}_2}} \right)\hat i\)
• B. \( - {\rm{\omega }}\left( {{{\rm{R}}_1} + {{\rm{R}}_2}} \right)\hat i\)
• C. \({\rm{\omega }}\left( {{{\rm{R}}_1} - {{\rm{R}}_2}} \right)\hat i\)
• D. \({\rm{\;\omega }}\left( {{{\rm{R}}_2} - {{\rm{R}}_1}} \right)\hat i\)