Q: Fact 1: Erosion causes a river to become deeper and wider. Fact 2: Water erosion has similar consequences as wind erosion. Given the two facts above, what can make a river deepen and widen?

OPT:
[a]. birds;
[b]. sunlight;
[c]. Sediment;
[d]. wind and water;
[e]. rainfall;
[f]. flooding;
[g]. weeds;
[h]. arteries;
The answer is:
[d].