In a DFD, an originator or receiver of data (external to the system) is shown using which symbol?

Introduction: Accurate symbol recognition is foundational to reading and creating data-flow diagrams. This item checks whether you can identify the external entity symbol for sources and sinks of data.

Given Data / Assumptions:

• Notation aligns to standard DFD practice.
• We distinguish process, data flow, data store, and external entity.

Concept / Approach: External entities are outside the system boundary but interact with it by supplying or consuming data. They are drawn as squares or rectangles. Processes are circles; data flows are arrows; data stores are open-ended bars.

Step-by-Step Solution: 1) Determine the role: originator or receiver external to the system. 2) Map the role to the correct DFD symbol. 3) The correct symbol is a square box: external entity.

Verification / Alternative check: Cross-reference any systems analysis handbook for DFD symbol tables showing squares for external entities.

Why Other Options Are Wrong: Option A: Circles represent processing steps.
Option B: Arrows represent data flows.
Option D: Parallel lines represent data stores.
Option E: Clouds are used in network diagrams, not standard DFDs.

Common Pitfalls: Confusing external entities with processes because both can be boxes in other diagram types. In DFDs, the square has a specific meaning.

Final Answer: A square box (external entity / source or sink)