You do NOT have to implement the design. The primary keys and foreign keys should be clearly identified. List any additional assumptions you have made. This is a database for a charitable organization. Both for its own purposes and for the IRS, it needs to keep track of all of its donations and the patrons who give them.
Patrons can be either businesses or individuals, and have a name, address, and phone number.
For businesses, a contact name is also needed. A patron may pledge a single gift, or many gifts, and the charity needs to know when each gift was given. For in-kind gifts, the charity records a description of the gift and its approximate value. Patrons may also volunteer their time.