A minimum cardinality is the minimum number of entity instances that may participate in a relationship instance.

Answer: Option A

In the context of data modeling with the Entity-Relationship (ER) model, minimum cardinality refers to the minimum number of entity instances that must participate in a relationship instance. It defines the minimum requirement for participation in a relationship.

For example, in a "Customer" and "Order" relationship where a customer may place zero or more orders, the minimum cardinality on the "Order" side would be zero, indicating that a customer can exist without placing any orders.

Conversely, if there was a requirement that every customer must place at least one order, the minimum cardinality on the "Order" side would be one, indicating that every customer must have at least one associated order.

Therefore, the statement that Option A: True is correct because the minimum cardinality indeed represents the minimum number of entity instances that may participate in a relationship instance.