Answer:
Option (3)
Explanation:
Volume of the cylinder = 40 ft³
Since, volume of a cylinder is given by the expression,
V =

Here, r = radius of the circular base
h = Height of the cylinder
40 =

------(1)
Volume of a cone =

By substituting the value of 'h' from equation (1)
Volume of the cone =

=
ft³
Therefore, Option (3) will be the correct option.