An oil company fills 1 over 12 of a tank in 1 over 3 hour. At this rate, which expression can be used to determine how long will it take for the tank to fill completely?
A) 1/12 x 3 hours
B) 1/3 x 12 hours
C) 1/3 x 1/12 hours
D) 3 ⋅ 12 hours