In plan B the price rises by 10%.
Thus the price rise is per week is $0.8
In plan A the price rise per week is $0.1
In plan C the price rise per week is
In plan D the price rise per week is $0.25
Considering all the plan the maximum price rise for each week is 0.8.
So the plan that would lead to $12 fastest is plan B.
The answer is plan B.