MathNet 2012 Question 42

The amount of ink used to produce a Mathematical Olympiad paper follows a strange rule: in odd years it increases by $50\%$ over the previous year; in even years it decreases by one sixth of the previous year's amount. After how many years will it first be at least three times the 2012 amount?
(A) 5 (B) 6 (C) 7 (D) 8 (E) 9.