In Chen ERD how would you make a chart about the following case?

A nonprofit organization depends on a number of different types of persons for its successful operations. The organization is interested in the following attributes for all of these persons: SSN, Name, Address, City/State/Zip, and Telephone. Three types of persons are of great interest: employees, volunteers, and donors. Employees can have a Date_Hired attribute, and volunteers only have a skill attribute. Donors only have a relationship (named Donates) with an Item entity type. A donor must have donated one or more items, and an item may have no donors, or one or more donors.

There are persons other than the employee, volunteers, and donors who are of interest to the organization, so that a person need not belong to any of these three grouping. On the other hand, at a given a person may belong to two or more of these groups (for example, employees and donor)

What are some assumptions you had to make?