What Is the Main Purpose of a Business Plan

What is the main purpose of a Business Plan?

A) to provide a 3-5 year road map outlining the company's operating, marketing, financial and HR intentions
B) to provide a 1 year estimate of the company's spending on operations and research/development
C) to provide a road map describing corporate competitors and its approach of competing in the market
D) to provide a document prepared for external financiers in order to apply for a loan
E) to outline the research and development areas of commercial interest to the company