Back in 1898 Triplett Had Children Wind Fishing Reels as Quickly

Back in 1898 Triplett had children wind fishing reels as quickly as they could. He found that

A) the children were fastest when observed by the experimenter.
B) winding times were faster without an audience than with an audience.
C) the children were faster when working in a pair rather than alone.
D) the children were faster working alone than with a partner.