Which of the Following Is a Characteristic of Time Series

Which of the following is a characteristic of time series (or trend) analysis?

A) Dollar changes and percentage changes in a company's financial statement lines are compared over several years.
B) All items are presented as a percentage of one selected item on a financial statement.
C) A statistic is calculated for the relationship between two items on a single financial statement or for two items on different financial statements.
D) Ratio increases and decreases are presented for the past two accounting periods.