Comprehensive Problem 13-84 (LO 13-1, LO 13-2, LO 13-3, LO 13-4, LO 13-5, LO 13-6) lan retired in June 2017 at the age of 69 (he turned 70 in August 2017). lan's retirement account was valued at $490,000 at the end of 2016 and $500,000 at the end of 2017. He has had all of his retirement accounts open for 15 years. What is lan's required minimum distribution for 2018 under each of the following alternative scenarios? (Leave no answer blank. Enter zero if applicable.) (Use Exhibit 13-3) Required: a. lan's retirement account is a traditional 401(k) account. b. lan's retirement account is a Roth 401(k) account. c. lan's retirement account is a traditional IRA. d. lan's retirement account is a Roth IRA a. Required minimum distribution b. Required minimum distribution C. Required minimum distribution d. Required minimum distribution