What tool is used to automate complex business processes in Salesforce?

Process Builder is the appropriate tool for automating complex business processes in Salesforce. It allows users to create workflows that can execute a series of actions based on changes to data in real-time or on a scheduled basis. With Process Builder, you can define criteria and specify multiple actions that should occur when those criteria are met, which enables the automation of intricate processes without the need for coding.

Unlike Workflow rules, which are more limited in functionality and can only perform a single action based on a trigger, Process Builder can handle multiple criteria and actions in a single interface, making it far more versatile for sophisticated business logic. Additionally, it surpasses Approval Processes, which are specifically designed for routing records through a series of approval steps rather than for general process automation, and it goes beyond Validation Rules, which primarily serve to ensure that certain conditions are met for data entry rather than automating actions based on data changes. Thus, Process Builder stands out as the best tool for automating complex business processes within Salesforce.