C#.NET — Identify the incorrect decision-control form among common if/else patterns.

Introduction / Context:
This tests recognition of valid if/else/else-if ordering and structure in C# decision control statements.

Given Data / Assumptions:

• We compare several forms to find the one that violates syntax or structure.

Concept / Approach:
In C#, else-if chains must place the else-if blocks before a final else block. After else appears, no further else-if can follow. Bracing style in examples is acceptable as shown.

Step-by-Step Solution:

Verification / Alternative check:
Try compiling each pattern: only option C fails because the parser does not allow else-if after else.

Why Other Options Are Wrong:

• A: simple if; valid.
• B: if/else; valid.
• D: if → else if → else; valid.
• E: multiple else if followed by else; valid.

Common Pitfalls:
Misordering else-if and else, or thinking that multiple else blocks are allowed (only one else is permitted at the end).

Final Answer:
Option C is the incorrect form.