lan retired in June 2015 at the age of 69 (he turned 70 in August 2015). lan's retirement account was valued at $540,000 at the end of 2014 and $550,000 at the end of 2015. He has had all of his retirement accounts open for 15 years. What is lan's required minimum distribution for 2016 under each of the following alternative scenarios? (Use Exhibit 13-3) (Leave no answer blank. Enter zero if applicable.) a. lan's retirement account is a traditional 401 (k) account. Required minimum distribution b. lan's retirement account is a Roth 401 (k) account. Required minimum distribution c. lan's retirement account is a traditional IRA. Required minimum distribution d. lan's retirement account is a Roth IRA Required minimum distribution