Airport security guards choose some travelers for an extra safety check. So far, the guards have chosen the 6th, 12th, 18th, and 24th travelers in line. Which of these people will most likley be chosen for the extra safety check?
A: The 25th traveler in line
B:The 26th traveler in line
C: The 30th traveler in line
D:The 34th traveler in line