Answer is C-SCAN.
SCAN is wrong because it works like elevator servicing requests while going up and coming down, whereas in this case if you observe series [126, 167, 199, 12, 36, 42, 51, 69 and 76 ], after 199 it suppose to scan 76 but not 12.
If SCAN then answer would be in the series-126,167,199,76,69,51,42,36,12]
So in C-SCAN starts from 100, 126,167, and after reaching 199, without servicing any request during return it will reach 0 initially, then it start servicing requests on the way from 0 [12,36,42,51,69 and 76].till it reaches end of the disk.