5. In 2014, a wealthy young couple, the spouses Tan, moved by the spirit of generosity and love for their hometown in Siquijor, decided to donate a one-hectare lot in favor of the province of Siquijor. The Deed of Donation pertinently provides: “The herein DONORS hereby voluntarily and freely give, transfer and convey, by way of unconditional donation, unto said DONEE, all of the rights, title and interest which the aforesaid DONORS have or which pertain to them and which they owned exclusively in the above-described real property over a one hectare portion of the same, solely for hospital site only and for no other purpose, where a provincial government hospital shall be constructed.” The donation was recorded in the Registry of Deeds, and a certificate of title to the property was transferred to the province of Siquijor. In accordance with the Deed of Donation, the construction of a hospital building was started in the following year. However, for reasons unknown, only the foundation of the hospital building has, to this day, been completed. Do the spouses Tan have valid grounds to revoke the donation? Explain briefly. (5 points)