C#.NET — Choose the correct method signature: receives (int, Single, double), returns decimal. Which definition is valid?

Introduction / Context:
The question is about proper C# method declaration syntax: where the return type goes, whether static is allowed, and what parameter types look like. You must identify the one header that is syntactically correct for a method returning decimal and accepting (int, Single, double).

Given Data / Assumptions:

• Return type must be decimal.
• Parameters: int, Single (System.Single), double.
• Method name: fun.

Concept / Approach:
In C#, the signature form is: [modifiers] return_type MethodName(parameter_list) { ... }. The return type precedes the method name. Either a static or an instance method is possible; using static is optional and valid here. Single is the CLR type for float and is allowed in a signature.

Step-by-Step Solution:

Verification / Alternative check:
Compiling option C succeeds; changing Single to float also works because float is an alias of System.Single.

Why Other Options Are Wrong:
A/D/E violate signature syntax or return rules; B is acceptable as an instance method but is not the intended best answer against this key.

Common Pitfalls:
Placing the return type after the parameter list, or thinking Single is not allowed.

Final Answer:
static decimal fun(int i, Single j, double k) { ... }