Which of the following structures of knowledge representation are the most purely syntactic?
A. Conceptual dependency
B. Predicate logic
C. Slot-and-filler
D. Nonmonotonic systems
Choose the correct answer from the options given below:

Correct option is B

A syntactic structure primarily focuses on the form or structure of the expressions rather than their meaning or semantics.
Conceptual Dependency (A):
· Definition: Conceptual Dependency (CD) is a framework for representing the meaning of natural language sentences. It emphasizes the semantic representation of actions and objects.
· Nature: Since it is focused on meaning rather than just structure, it is not purely syntactic.
Predicate Logic (B):
· Definition: Predicate logic is a formal system in which formulas represent relations among objects. It uses variables, predicates, and quantifiers to express logical statements.
· Nature: Predicate logic has a formal syntax for expressing statements and is concerned with the structure of expressions, making it syntactic.
Slot-and-Filler (C):
· Definition: The slot-and-filler structure is a way to represent knowledge by associating attributes (slots) with their values (fillers). It is often used in frame-based systems.
· Nature: This structure is concerned with how information is organized, focusing on the structure rather than meaning, making it syntactic.
Nonmonotonic Systems (D):
· Definition: Nonmonotonic reasoning systems allow the introduction of new information to invalidate previous conclusions, unlike traditional logic systems.
· Nature: These systems are more concerned with the reasoning process and the semantics of information updates, not just the structure, making them less syntactic.
On the given above information we can analyze that, the structures that are most purely syntactic are:
B. Predicate logic
C. Slot-and-filler