Which of the following equations represent a graph with the most rapid rate of change?
AY=6 (3^x)
BY=2 (4^x)
CY=3 (6^x)
DY=4 (2^x)
AY=6 (3^x)
BY=2 (4^x)
CY=3 (6^x)
DY=4 (2^x)