C

问题如下：

Among the following, which one accurately acts as a simultaneous signal of economic activity?

选项：

A.Average duration of unemployment

B.Average weekly hours, manufacturing

C.Employees on non-agricultural payrolls

解释：

1. Average duration of unemployment
   Incorrect. The time individuals remain unemployed tends to extend or contract based on the overall economic health. Companies generally delay layoffs until a downturn is apparent and hesitate to hire until an upswing is more certain. This makes the average duration of unemployment a lagging indicator, reflecting past economic trends.

2. Average weekly hours, manufacturing
   Incorrect. When economic uncertainty arises, firms often modify their workers' hours before making more permanent decisions about layoffs or hiring. As such, changes in average weekly hours in manufacturing can provide early clues about future economic trends, classifying it as a leading indicator.

3. Employees on non-agricultural payrolls
   Correct. As economic shifts become evident, organizations will adapt their staffing levels in non-agricultural sectors. This mirrors real-time economic performance, making employees on non-agricultural payrolls a coincident indicator, representing current economic conditions.

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