Answer:
True: A, B, F
False: C, D, E
Explanation:
volume of a cone:

(where r is the radius and h is the height)
Area of the base = area of a circle:

(where r is the radius)
Cone A
radius (r) = 9
height (h) = 12


Cone B
radius (r) = 7
height (h) = 18


Cone C
diameter = 18 ⇒ radius (r) = 9
height (h) = 9


True: A, B, F
False: C, D, E