Ratio of A and B: Is there Variation?

The phrase 'the variation in the ratio of A and B' is grammatically correct, but it can be phrased more clearly. Here are two options for improving the clarity of the statement:

'Is there a variation in the ratio of A and B?'

'Does the ratio of A and B vary?'

These revised phrases explicitly ask about the presence or absence of change in the ratio, making the intended meaning more transparent.