459 water flows... not sure if this is right but it’s what calculated so good luck
Oi
Just calculating the differential. Step by step:

If you want to know where the tangent has no slope:
Answer:
D
Step-by-step explanation:
firstly,y-intercept, x=0,A and b wrong
sub x=0
0.25⁰=1
(0,1)
D