C#.NET — Which snippets correctly classify an integer as Odd or Even (consider operators and definite assignment)?

Introduction / Context:
The task is to identify which code fragments are valid C# for printing or storing whether an integer a is "Odd" or "Even". Beyond logic, you must check language details such as supported operators and definite assignment rules for local variables.

Given Data / Assumptions:

• Snippets 1 and 4 declare int a; without assigning a value before using it.
• Snippets 2 and 3 use the Mod operator keyword.
• We evaluate both syntax and compile-time rules.

Concept / Approach:
In C#, a local variable must be definitely assigned before its value is read. Also, C# uses the % operator for remainder; the VB-style Mod keyword is not a C# operator. Therefore, even if the logic looks fine, using an uninitialized local or an unsupported operator makes a snippet invalid.

Step-by-Step Solution:

Verification / Alternative check:
Fixing any snippet requires (a) assigning a first, e.g., int a = 7;, and (b) replacing Mod with % where present.

Why Other Options Are Wrong:

• A/B/C/D claim one or more invalid snippets are correct; each relies on uninitialized locals or the non-existent Mod operator in C#.

Common Pitfalls:
Assuming VB syntax applies to C#, or overlooking the compiler’s definite assignment checks for locals.

Final Answer:
None of these