If 2 is added to each odd digit and 1 is subtracted from each even digit in the number 8354671, then how many digits will appear more than once in the new number thus formed?

Given: 8354671

If 2 is added to each odd digit and 1 is subtracted from each even digit.

8 (even) → 8 − 1 = 7

3 (odd) → 3 + 2 = 5

5 (odd) → 5 + 2 = 7

4 (even) → 4 − 1 = 3

6 (even) → 6 − 1 = 5

7 (odd) → 7 + 2 = 9

1 (odd) → 1 + 2 = 3

New number = 7 5 7 3 5 9 3

Digits appearing more than once = 7, 5, 3

So, three digits will appear more than once in the new number thus formed.

Thus, correct option is (d).