C#.NET — Implement a read-only property Length correctly in a class.

Introduction / Context:This item tests your ability to recognize a correct read-only property pattern in C#. A read-only property must expose only a get accessor that returns a backing value. Any presence of a set accessor (or infinite self-reference) violates the read-only or correctness requirement.

Given Data / Assumptions:

• The property is named Length.
• We want a proper implementation that compiles and is read-only.

Concept / Approach:A traditional read-only property uses a private backing field and provides only a get block that returns that field. Expression-bodied members are also valid modern syntax, but the question typically expects the classic full-property form. Beware of accidental recursion (return Length;) and invalid keywords such as “Readonly” in accessors (not C# syntax).

Step-by-Step Solution:

Verification / Alternative check:Compiling Option A succeeds; reading Sample.Length returns the stored value of len. Attempts to assign Sample.Length will fail since no setter exists.

Why Other Options Are Wrong:

• B: Recursive getter; incorrect.
• C: Not read-only by definition.
• D: Uses an invalid keyword in accessor position.
• E: Although valid in modern C#, the key expects the classic pattern; we retain A as the correct response.

Common Pitfalls:Returning the property from itself; forgetting that “readonly” is a field modifier, not an accessor keyword.

Final Answer:Option A is the correct read-only property implementation.