Explanation
A tabletop exercise is a simulated scenario that tests the effectiveness of a security incident response plan. It involves gathering the relevant stakeholders and walking through the steps of the plan, identifying any gaps or issues that need to be addressed. A tabletop exercise is a good way to validate the documentation created by the security manager and ensure that the team is prepared for various types of security incidents.
References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, Chapter 6: Risk Management, page 2841. CompTIA Security+ Certification Kit: Exam SY0-701, 7th Edition, Chapter 6: Risk Management, page 2842.

Recovery Time Objective (RTO) defines the maximum acceptable downtime before business operations must be restored. It helps organizations set expectations for recovery speed and prioritize system restoration accordingly.
A (likelihood of an incident and cost) relates to risk assessment, not RTO.
B (roles and responsibilities) falls under incident response planning, not RTO.
C (state of restored systems) is covered by Recovery Point Objective (RPO), not RTO.
Reference:
CompTIA Security+ SY0-701 Official Study Guide, Security Program Management and Oversight domain.

A hash is an algorithm used to verify data integrity by generating a fixed-size string of characters from input data. If even a single bit of the input data changes, the hash value will change, allowing users to detect any modification to the data. Hashing algorithms like SHA-256 and MD5 are commonly used to ensure data has not been altered.
Reference:
CompTIA Security+ SY0-701 Course Content: Domain 6: Cryptography and PKI, which discusses the role of hashing in verifying data integrity.