This is a federal income tax question. I do not understand why the time period requirement for c and d are until 12/31/2018 and 6/30/2018 respectively. Isnt it supposed to be 2 years since the years you get the proceeds? I thought it should be until 12/31/2017 and 6/30/2017. The answers to the question are given. Can someone explain why i am wrong?

22 which of the following satisfy the time period requirement for postponement of gain as a 1033 (nonrecognition of gain from an involuntary conversion) involuntary conversion? a. Al's business warehouse is destroyed by a tomado on October 31, 2015. Al is a calendar year taxpayer. He in another warehouse to be used in his business on December 29, 2017 b. Heather's personal residence is destroyed by fire on October 31, 2015. She is a calendar year taxpayer. She receives insurance proceeds on December 5, 2015. She purchases another principal residence with the proceeds on October 31, 2017. c. Mack's office building is condemned by the city as part of a road construction project. The date of the ndemnation is October 31, 2015. He is a calendar year taxpayer. He receives condemnation proceeds from the city on that date. He purchases another office building with the proceeds on December 5, 2018. d. Lizzy's business automobile is destroyed in an accident on October 31, 2015. Lizzy is a fiscal year taxpayer with the fiscal year ending on June 30th. She receives i nsurance proceeds on December 5, 2015. She purchases