The generation time g for a particular bacteria is the time it takes for the population to double. the bacteria increase in population is shown by the formula (see image) , where t is the time period of the population increase, a is the number of bacteria at the beginning of the time period, and p is the number of bacteria at the end of the time period. if the generation time for the bacteria is 6 hours, how long will it take 8 of these bacteria to multiply into a colony of 7681 bacteria? round to the nearest hour.

a. 177 hours
b. 76 hours
c. 4 hours
d. 85 hours