C. The bottom of the streambed is lower than the water table, and intersects the aquifer. Because of this, water still enters the stream from the ground.
This option explains that when the streambed is lower than the surrounding water table, groundwater can flow into the stream, contributing to its flow due to the difference in elevation between the water table and the streambed. This process helps maintain the flow of water in the stream, especially in times when surface water (like precipitation) may not be sufficient.