Heavy rainfall increases stream velocity, which increases channel erosion, which increases channel width, Which of the following correctly describes the sequence of events described in the statement above?
a) Heavy rainfall → Increased external friction → Channel erosion → Increased stream velocity
b) Heavy rainfall → Increased channel width → Channel erosion → Increased stream velocity
c) Heavy rainfall → Increased stream velocity → Channel erosion → Increased channel width
d) Heavy rainfall → Increased stream velocity → Channel width → External friction