Answer:
The answer is A.
Explanation:
During logarithmic growth phase bacteria grows exponentially doubling every x minutes (x depends on the species). In this question doubling time/generation time is every 15 minutes and log phase takes 5 hours, which equals to the 300 minutes. During 300 minutes bacteria doubles 20 times (300/15 = 20) which equals 2^20. Bacteria culture has been started with 1000 bacterial cells so it must be added to the calculation therefore right answer is: 1000 X 2^20.