City X has a population 8 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?	Choose the correct choice from the following answers:
A) 1 : 8
B) 1 : 4
C) 2 : 1
D) 4 : 1
E) 16 : 1

Rationale: "x = 8 y , y = 2 * z x : y , y : z 8 : 1 , 2 : 1 16 : 2 , 2 : 1 so , x : z = 16 : 1 ( e )"
Answer: E