Mr Jacques wrote a bonus problem on the board. I f Gina correctly answer, she gets extra time to read. The problem is to write a statement that correctly relates the numbers 9 and 18. Which should Gina write?
a) 18 is a common multiple of 9
and 18
b) 27 is a common multiple of 9 and 18
c) 9 is a multiple of 18
d)18 is a factor of 9