If the generation time of a bacterium is 40 minutes and a culture containing \[{{10}^{7}}\] cells/ml is grown for 4 hours, then calculate its population after that period.

• A. \[64\times {{10}^{7}}\]    
• B. \[32\times {{10}^{7}}\]
• C. \[6\times {{10}^{7}}\]                         
• D. \[40\times {{10}^{7}}\]