Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii \[{{R}_{1}}\]and \[{{R}_{2}}\] respectively. The ratio of the mass of X to that of Y is

• A. \[{{({{R}_{1}}/{{R}_{2}})}^{1/2}}\]              
• B. \[{{R}_{2}}/{{R}_{1}}\]
• C. \[{{({{R}_{1}}/{{R}_{2}})}^{2}}\]                 
• D. \[{{R}_{1}}/{{R}_{2}}\]