Find the odd number / letters / word from the given alternative:

The answer is D. 5686.

In each of the other options, the sum of the first two digits is equal to the third digit. For example, in 1236, 1 + 2 = 3. In 2346, 2 + 3 = 5. In 4566, 4 + 5 = 9. However, in 5686, 5 + 6 = 11, which is not equal to 8.