TPO28 reading第一篇求助~

TPO28 reading第一篇求助~
第11题 If the water table intersects the land surface,groundwater will flow out onto the surface at springs,either to be collectedthere or to subsequently flow father along a drainage.C.Groundwater may be drained ifsprings occur where the water table intersects the land surface.D.Where the water table meets theland surface,groundwater flows out through surface springs.D明明没说drain的事,为什么要选D?C错在哪了?