Explanation:

A Revenue Cloud consultant needs to understand the client’s business, their products or services, and their sales process before they can effectively scope a Revenue Cloud project.

A. A sample proposal the client provides to their customers: This document can give the consultant insights into the client’s current sales process, pricing strategies, and customer interactions1.

B. Brochures that provide detail to the products and services the client offers: These materials can help the consultant understand the client’s product offerings, their unique selling points, and how they position themselves in the market1.

D. An approval matrix documentation that describes the approvals needed before a quote is sent to the customer: This document can help the consultant understand the client’s internal approval processes, which is crucial for configuring the approval workflows in Revenue Cloud2.

C. The latest release notes found at help.salesforce.com>salesforce CPQ patch notes: While these notes are important for staying updated on the latest features and bug fixes in Salesforce CPQ, they may not directly help the consultant understand the client’s specific project requirements3.

E. The client’s income statements and balance sheet: While these financial documents can provide valuable insights into the client’s financial health and performance, they may not directly contribute to understanding the client’s Revenue Cloud project requirements1. References: Salesforce Revenue Cloud documents1, Salesforce Approval Processes2, Salesforce CPQ Patch Notes3.