C#.NET — Identify invalid switch-case labels and default usage. switch (id) { case 6: grp = "Grp B"; break; case 13: grp = "Grp D"; break; case 1: grp = "Grp A"; break; case ls > 20: grp = "Grp E"; break; case Else: grp = "Grp F"; break; }

Introduction / Context:
This tests which constructs are valid inside a C# switch statement and how to specify a default branch.

Given Data / Assumptions:

• Valid numeric cases exist: 6, 13, 1.
• Two suspicious labels: case ls > 20 and case Else.

Concept / Approach:
Case labels must be constant expressions of the same type as the switch expression. Relational expressions (like ls > 20) are not allowed. The default branch must be written as default:, not case Else: .

Step-by-Step Solution:

Verification / Alternative check:
Replace "case ls > 20:" with a proper if/else before the switch or compute a bucketed integer; replace "case Else:" with "default:".

Why Other Options Are Wrong:

• B: claims no error; wrong.
• C: only flags Else, ignoring ls > 20; wrong.
• D: default is optional in C#; lack of it is not an error.
• E: ordering is not enforced; any order is acceptable.

Common Pitfalls:
Trying to embed boolean conditions in case labels and misusing Else instead of default.

Final Answer:
Compiler will report an error in case ls > 20 as well as in case Else.