C#.NET indexers — Which statements are correct about indexer definitions and interface indexers?

Introduction / Context:
Indexers are property-like members that use parameters to provide array-style access to objects. Understanding their signatures and how they are declared on interfaces is essential for robust API design.

Given Data / Assumptions:

• We evaluate five statements about indexers and their accessors.
• We consider both class/struct indexers and interface indexers.

Concept / Approach:
Indexer signature is defined by the number and types of parameters (and modifiers like ref/out, when applicable). Indexers resemble properties, but accessors take parameters. Interface members, including indexers, have no bodies, and their accessors cannot use access modifiers; they simply declare get and/or set.

Step-by-Step Solution:

Verification / Alternative check:
Define an interface with int this[int i] { get; set; }; note there are no bodies and no accessor-level modifiers.

Why Other Options Are Wrong:

• Options C: Both statements selected are false.
• Option A: Mixes one true with two false statements.
• Option D: Omits statement 1; incomplete.

Common Pitfalls:
Trying to add public/private to interface accessors or writing method bodies inside interfaces (not allowed).

Final Answer:
1, 2, 4