The answer is A because in order to convert a fraction to a ratio, you first write down the numerator which in this case is 3. Then you write a colon to separate the 2 numbers and write down the denominator which is 16. So in the ratio would be 3:16 or 16:3. In some cases, you may have to simplify the ratio, but in this case, it cannot be simplified any further, so A is the right answer
