Consider an instantaneous point source injection of a conservative organic tracer into a river. A given mass of the tracer is injected at two locations in the river and concentrations are measured versus time 50 meters downstream of the injection point for both locations. For location A, the center of mass of the breakthrough curve arrives in 15 seconds and the peak concentration is a lower than for the breakthrough curve at location B, where the center of mass arrives in 20 seconds. Which of the following statements is the clearly true?
A. The velocity in reach B is higher than reach A.
B. Biodegradation or sorption is larger in reach A.
C.The dispersion coefficient is larger in reach A.
D. The dispersion coefficient is larger in reach B.