Task: Class Definition Understanding (ontology: Earth_Environment/OBOE)

Which of the following definitions best describes 'Identifier'?

A. provides an alphanumeric string of characters to refer to an entity. A the concept is typically used to uniquely identify an entity such as a sample or an individual specimen such as a tree or a rock sample.
B. Conductivity is the reciprocal (inverse) of electrical resistivity, ρ, and has the SI units of siemens per metre (S·m-1). "siemens" is used for both singular and plural.
C. provides an identifying sequence of characters to refer to an entity within a context. An the concept can be unique within a local context or a global context.
D. provides a character phrase to refer to an entity. A the concept is typically used to reference an entity. For example, the the concept for a particular instance of a lake might be 'Lake Tahoe'.

Answer: provides an identifying sequence of characters to refer to an entity within a context. An the concept can be unique within a local context or a global context.