See the solution below
Explanation/Reference:
1. Apex is a procedural scripting language executed byfoix-e.com.
2. It uses a Java-like syntax, acts like database stored procedures.
3. It runs natively on sales force servers, more powerful and faster than non-server code.
4. It adds business logic to most system events - button clicks, related record updates, s-control displays, data loads

Explanation/references: You can add up to four objects to a custom report
type.
However, some of the object combinations you choose may not be able to reach that limit.

Section: Volume D

1. Alerting
2. Tasking 3-Routing/assigning/escalation
4.Updating
5.Integrating
6.Mass communication