The term which is used to represent real-world concept or object is classified asa.entityb.Attributec.relationshipd.object

The term which is used to represent a real-world concept or object is classified as an "entity". This term is often used in the context of databases and information systems, where an entity can represent a tangible object (like a person or a car) or an intangible concept (like an event or an idea).

Here's a step-by-step breakdown:

1. Real-world concepts or objects need to be represented in databases and information systems for processing and analysis.

2. These concepts or objects can be tangible (like a person, a car, a book) or intangible (like an event, an idea, a course).

3. The term used to represent these real-world concepts or objects in databases and information systems is "entity".

4. Therefore, the answer to your question is a. entity.