a conservationist is tracking the number of a rare type of tree in a forest as it recovers from a fire. During the first 4 years after the fire, she records 2,6,18, and 54 trees. If this trend continues, which expression can be used to find the number of trees after n years? A. 2(3)n-1, B. 2 + 3 (n-1), C. 3(n-1) D.3(2)n-1