Which alphabet replaces the question mark ? 63 O 49 72 T 37 96 L 15 14 ? 58

6-3 = 3 9-4 = 5 (3x5=15) 15=O
7-2 = 5 7-3 = 4 (5x4=20) 20=T
9-6 = 3 5-1 = 4 (3x4=12) 12=L

Similarly, 4-1 = 3 8-5 = 1 (3x1=3) 3=C