Which statement is not correct?

a. The changeability property specifies the type of operations that are allowed on either variable values or links.

b. OCL constraints are defined in a procedural way.

c. OCL constraints can be used for various purposes, such as to specify invariants for classes, to specify pre- and post-conditions for methods, to navigate between classes or to define constraints on operations.

d. In UML, dependency defines a “using” relationship that states that a change in the specification of a UML modeling concept may affect another modeling concept that uses it.