The third dot is my answer. But don't take it for granted. Try it yourself and see what you come out with!
Answer: Level of the liquid dropping at 28.28 inch/second when the liquid is 2 inches deep.
Step-by-step explanation:
Since we have given that
Height = 9 inches
Diameter = 6 inches
Radius = 3 inches
So, 
Volume of cone is given by

By differentiating with respect to time t, we get that

Now, the liquid drips out the bottom of the filter at the constant rate of 4 cubic inches per second, ie 
and h = 2 inches deep.

Hence, level of the liquid dropping at 28.28 inch/second when the liquid is 2 inches deep.
Pretty sure it is A. Hopefully this helps and sorry if I am mistaken.
Answer:
2
Step-by-step explanation: