12,2,26,12,34,__________

Pattern: first number minus 10 gives second: 12-10=2. Third minus 14 gives fourth: 26-12=14. Fifth minus 22 gives sixth: 34-22=12. The subtrahends increase: 10,14,22 (differences: 4,8). Alternatively: 12+14=26, 2+10=12, 26+8=34, 12+?=12. The additions to first numbers are 14,8 (decreasing by 6). Pattern: add 14, then 8, then 2 (continuing -6): 12+2=14 (not matching). Let me reconsider: 12,2,26,12,34,. Pairs: (12,2), (26,12), (34,). First of pair minus second: 10,14,?. If pattern is +4, then 10,14,18 so 34-18=16 (not option). Actually: 12/2=6, 26/2=13, 34/2=17. 6,13,17. Then 2,12,__. 2+10=12, 12+5=17? Not matching. Given answer C=12, the pattern might be simpler.