一平面简谐波沿x轴正向传播，已知P点（xp＝L）的振动方程为y＝Acos（ωt＋φ0），则波动方程为（　　）。

A、<img width="219" height="23" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/ec7597a2-2ed7-408c-8a85-1da329976e2f.png" />

B、<img width="195" height="23" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/35af2f28-15f4-481a-a312-84c582ce6493.png" />

C、y＝Acos[t－（x/u）]

D、<img width="222" height="20" src="http://admintk.100xuexi.com/UpLoadImage/2013-05-07/91303a5a-c735-4304-acf7-6d810265912a.png" />