In 2017, Susan Tells the Art Museum, a Private Not-For-Profit

In 2017, Susan tells The Art Museum, a private not-for-profit organization, that she has named the museum in her will. When should the organization recognize the contribution revenue?

A) When the Museum receives the contribution.
B) Only after Susan dies and the will is declared valid.
C) Ratably over a five year period beginning in 2017.
D) All in 2017.