By convention, all primary keys are bold underlined and foreign keys are bold.

$$ a$)$ EMPLOYEE$\_$SALES$\_$OFFICE: EmployeeID, OfficeNumber EMPLOYEE: EmployeelD, Employee$\_$Name SALES$\_$OFFICE: OfficeNumber, Location

$$ b$)$ EMPLOYEE$\_$SALES$\_$OFFICE: EmployeelD, Employee$\_$Name, OfficeNumber, Location EMPLOYEE: EmployeeID, Employee$\_$Name SALES$\_$OFFICE: OfficeNumber, Location

c$)$ EMPLOYEE: EmployeeID, Employee$\_$Name, OfficeNumber SALES$\_$OFFICE: OfficeNumber, Location

$$ d$)$ EMPLOYEE: EmployeelD, Employee$\_$Name SALES$\_$OFFICE: OfficeNumber, Location, EmployeelD

$$ e$)$ EMPLOYEE: EmployeelD, Employee$\_$Name SALES$\_$OFFICE: OfficeNumber, Location