If the work of wind, water, and time causes a river to become deeper and wider, then the work of what causes a river to become deeper and wider?

Answer choices:
- looseness of dirt or compost
 - just time
 - Veins and arteries.
 - just wind
 - Physical weathering
 - The area was once underwater
 - just water
 - wind, water, and time

 

        wind, water, and time  