One of the reasons bacteria can be so deadly is because they multiply very quickly. e. coli has a doubling time of around 15 minutes. this means that if 100 bacteria are left alone for 2 hours, they will multiply to become:
12,400 bacteria
18,400 bacteria
25,600 bacteria
36,600 bacteria

The correct answer is - 25600 bacteria.

Explanation:

Bacteria can divide and produce double their population very quickly. As mentioned in the question bacteria multiply every 15 minutes to their double number. Finding the number of bacteria after 2 hours is simple mathematics. Two hours means 120 minutes and dividing it to 15. The result will be 8 which mean the bacteria double their colony 8 time so,

100×2 to the power 8 = 100 (initial number of bacteria)×2×2×2×2×2×2×2×2= 25600

Thus, the correct answer is option- 25600 bacteria.