Final answer:
Balance sheets provide two years of comparative financial information and income statements provide three years of information for historical analysis.
Step-by-step explanation:
The reason why the SEC requires balance sheets to provide two years of comparative financial information and income statements to provide three years of information is __b. Historical analysis__. This requirement allows for the analysis of financial performance over time and helps to identify trends and changes in a company's financial position. By comparing financial information from different periods, investors and analysts can assess the company's stability, growth, and profitability.