Karen is building a website that is expected to have a minimum of 1000 users continually over the course of 24 hours. For 8 hours each day, traffic is expected to be at about 1800 users. What EC2 buying options should she use to handle all the traffic and be most cost-effective? Choose the Correct Answer
A. Karen should rely solely on spot instances since that will be the cheapest option
B. Karen should buy enough reserved instance capacity to handle all 1800 users and probably buy a little more capacity just in case it is needed
C. Karen should buy reserved instances with enough capacity to cover the baseline of 1000 users, then rely on on-demand instances for the 8 hour period of increased traffic each day
D. Karen should buy reserved instances with enough capacity to cover the baseline of 1000 users, then rely on spot instances for the 8 hour period of increased traffic each day