What is a null value?

A null value refers to a fictional product or service that a company includes in its inventory to maintain a sense of completeness, even though it has no actual use or existence.
A null value is a placeholder used for voided or canceled transactions in a company’s accounting records, typically resulting from errors, fraud detection, or other irregularities.
A null value is a special character added to your competitive analysis reporting that represents the absence of competition in a specific market or industry, indicating a monopoly or lack of alternatives for consumers.
A null value is a placeholder used when the value in a property is either unknown or missing.

The correct answer is:

A null value is a placeholder used when the value in a property is either unknown or missing.