The radioactivity of sample is \[{{R}_{1}}\] at a time \[{{T}_{1}}\] and \[{{R}_{2}}\] at a time\[{{T}_{2}}\]. If the half-life of the specimen is T, the number of atoms that have disintegrated in the time (\[{{T}_{2}}-{{T}_{1}}\]) is proportional to

• A. \[{{R}_{1}}{{T}_{1}}-{{R}_{2}}{{T}_{2}}\]  
• B. \[{{R}_{1}}-{{R}_{2}}\]
• C. \[\frac{({{R}_{1}}-{{R}_{2}})}{4}\]     
• D. \[({{R}_{1}}-{{R}_{2}})\]