Spot instances are cloud resources that are available at a lower price than on-demand instances, but can be terminated by the cloud provider at any time based on supply and demand. Therefore, the application that will run on these instances needs to handle unpredictable instance termination, such as by saving state information, implementing fault tolerance, or using checkpoints12.
The other options are not directly related to the use of spot instances. The application may or may not need to store data in a database, depending on its functionality and design. There is no inherent restriction for distributed network communications when using spot instances, as long as the application can handle network latency and bandwidth issues. Resource-intensive compute loads are not forbidden, but they may increase the likelihood of instance termination, as the cloud provider may reclaim the resources for higher-paying customers.
Reference:
[CompTIA Cloud Essentials+ CLO-002 Study Guide], Chapter 2: Business Principles of Cloud Environments, Section 2.4: Cloud Service Costing, p. 81-82
[CompTIA Cloud+ CV0-003 Study Guide], Chapter 6: Optimizing the Cloud Environment, Section 6.3: Cloud Optimization Techniques, p. 287-288
[CompTIA Cloud Essentials+ CLO-002 Study Guide], ISBN: 978-1-119-64768-9, Publisher: Wiley
[CompTIA Cloud+ CV0-003 Study Guide], ISBN: 978-1-119-64767-2, Publisher: Wiley