Both rates and ratios are a comparison of two numbers. A rate is simply a specific type of ratio. The difference is that a rate is a comparison of two numbers with different units, whereas a ratio compares two numbers with the same unit. For example, in a room full of students, there are 10 boys and 5 girls. This means the ratio of boys to girls is 10:5.
If we rely solely on mathematics then the answer must be A. The other options seem to be from economy so it has nothing with mathematics. Please make sure that this is math task then answer.
