What Did Youngstrom Et Al

What did Youngstrom et al. (2004) find when identifying bipolar disorders among youth?

A) The prediction of bipolar disorder was best when combining parent reports with youth reports.
B) The prediction of bipolar disorder was not improved when combining parent reports with youth reports.
C) The prediction of bipolar disorder was best when combining teacher reports with youth reports.
D) The prediction of bipolar disorder was not improved when combining teacher reports with youth reports.