c)

d)

4.7.3

4.7.4

4.7.5

Males and Females subclasses are complete. Mothers and Fathers are partial. All subclasses are disjoint.

4.7.6

4.7.7

4.7.8

We convert the ternary relationship Contracts into three binary relationships between a new entity set Contracts and existing entity sets.

4.7.9 a)