Which of the Following Statements About Financial Statement Analysis Is

Which of the following statements about financial statement analysis is incorrect?

A) In horizontal percentage analysis,an item from the financial statements is expressed as a percentage of the same item from a previous year's financial statements.
B) Vertical analysis compares two or more financial statement items within the same time period.
C) Horizontal analysis for several years can be done by choosing one year as a base year and calculating increases or decreases in relation to that year.
D) The reason behind a financial statement ratio or percentage analysis result is usually self-evident and does not require further study or analysis.