SOLUTION
We are told that Christine has 9 shinning rings, and that if 5 of them are gold, how many are not gold?
Let the number of the rings that are not gold be n,
Since she has 9 rings and 5 are gold, then the numbers that are not gold which is n becomes

So,

If we bring -5 to meet n, then the minus sign becomes a plus sign, we have

Hence, the answer is option D
