On December 6, 2018, Kestrel Company (a calendar year taxpayer) authorizes a cash donation of $50,000 to the Memphis Public Library. The pledge is carried out as follows: $15,000 on December 12, 2018; $25,000 on February 13, 2019; and $10,000 on May 10, 2019. What are the alternatives for the year of the charitable contribution deduction if Kestrel is:

a. An accrual basis partnership?

b. An accrual basis C corporation?

c. What is the result under parts (a) and (b) if Kestrel is a cash basis taxpayer?