The sequence follows the pattern:
- D, F, H, J → Letters in increasing order with a step of 2.
- 4, 6, 8, 10 → Numbers in increasing order with a step of 2.
So, the next letter after J is L (2 steps forward), and the next number after 10 is 12 (2 steps forward).
Thus, the correct answer is (C) L-12.