The correct option is A 15.87m
Consider the wire and pole system as a right angled triangle such that length of pole is the perpendicular, length of wire the hypotenuse and distance between the base of pole and the stack is the base, such that, H = 24 m, P = 18 m
Now, from Pythagoras theorem,
H2=P2+B2
242=182+B2
576=324+B2
B2=252
B=15.87 m
Thus, distance between the base of the pole and the stack is 15.87 m