What is the two-digit number whose first digit is a and the second digit is b?. The number is greater than 9. I. The number is multiple of 51. II. The sum of the digits a and b is 6

1. A Option A: I alone sufficient while II alone not sufficient to answer
2. B Option B: II alone sufficient while I alone not sufficient to answer
3. C Option C: Either I or II alone sufficient to answer
4. D Option D: Both I and II are not sufficient to answer
5. E Option E: Both I and II are necessary to answer

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