You are developing a YANG-based policy model to encode the type of entity that is connected to a given interface, such as partner, supplier, customer, or distributor. Which YANG statement limits any…

The `when` statement in YANG is used to define a condition that must be satisfied for a data node to be valid or to exist. This mechanism allows for conditional data modeling, meaning that certain configuration actions or data structures are only allowed or active if the `when` condition evaluates to true, thereby limiting configuration possibilities.

The `case` statement is used within a `choice` statement to define alternative branches of data, not to limit configuration actions based on conditions.

The `enumeration` statement defines a set of allowed named values for a leaf, restricting the possible values but not the configuration action itself based on external conditions.

The `contains` keyword is not a standard YANG statement; it might refer to conceptual containment but not a specific statement for limiting configuration actions.