It Is Appropriate to Use the Two Standard Deviation Procedure

It is appropriate to use the two standard deviation procedure when:

A) The outcome variable is at the interval or ratio level of measurement, and the baseline data are unstable.
B) The baseline data are stable, and the outcome variable is at the nominal level of measurement.
C) The baseline data are relatively flat, lacking a pronounced increasing or decreasing trend, and the outcome variable is at the interval or ratio level of measurement.
D) The baseline data are stable and have a pronounced increasing or decreasing trend.