To Identify the Onset of a Recession, the National Bureau

To identify the onset of a recession, the National Bureau of Economic Research (NBER) Business Cycle Dating Committee,

A) tracks real GDP and nominal GDP for two consecutive quarters only.
B) uses a range of indicators including real GDP, employment and income.
C) identifies economic activity solely with real GDP.
D) uses procedure that determines the dates of peaks and troughs mainly on the basis of employment.