C#.NET enums: choose all correct placement and typing rules.

Introduction / Context:
This question validates knowledge of where enums can be declared and which underlying numeric types are allowed in C#.NET.

Given Data / Assumptions (Statements):

• 1) An enum can be declared inside a class.
• 2) An enum can take Single, Double or Decimal values.
• 3) An enum can be declared outside a class.
• 4) An enum can be declared inside/outside a namespace.
• 5) An object can be assigned to an enum variable.

Concept / Approach:
Enums can be declared at namespace scope or nested inside classes/structs. Underlying types must be integral: byte, sbyte, short, ushort, int, uint, long, or ulong. Floating-point and decimal are not allowed. Enum variables must hold values of that enum’s underlying integral domain, not arbitrary object references.

Step-by-Step Evaluation:

Verification / Alternative check:
Declare test enums with : byte or : long to confirm valid underlying types. Attempting : float or : decimal results in a compile error.

Why Other Options Are Wrong:
Any choice including statement 2 or 5 is invalid due to incorrect typing rules for enums.

Common Pitfalls:
Assuming any numeric type works; only integral types are valid. Also, forgetting that nested enums default to member accessibility rules of the containing type.

Final Answer:
1, 3, 4