Austin has $18000 in his savings account today. He earns interest at 4% p.a. effective. He plans to make the following withdrawals from his account $9800 in 3 years and $7100 in 12 years. He will still have $X left in his bank account right after the last withdrawal. Which one(s) of the following equations can be used to find $X? (There may be more than one correct answer. You will lose mark by picking a wrong answer. The minimum mark for the question is zero.) Select one or more: a. X = 18000 - 9800 - (1 + 0,04)3 - 7100 - (1 + 0.04)12 b. 18000 = 9800 . (1 + 0.04)- + 7100 (1 + 0.04)-12 + x = (1 + 0,04)-12 c. None of the equations can be used to find $X. d. X = 18000(1 + 0.04)12 - 9800(1 + 0.04)' - 7100 e. X = 18000 - 9800 = (1 + 0.04)'- 7100 f. X = 18000 - (1 + 0.04)12 - 9800 - (1 + 0.04)3 - 7100(1 + 0.04)12