Which of the following statements is correct regarding C# selection statements?

Introduction / Context:
This question tests knowledge of how C# selection statements behave, particularly if/else and switch.

Given Data / Assumptions:

• We evaluate five independent statements and must pick one correct statement.

Concept / Approach:
In C#, if evaluates a Boolean expression and selects a branch accordingly. switch requires unique case values and, unlike C, does not allow implicit fall-through between non-empty cases.

Step-by-Step Solution:

Verification / Alternative check:
Any C# specification summary confirms D; B and E are explicitly disallowed; A contradicts common usage.

Why Other Options Are Wrong:

• A: else-if is the normal extension.
• B: Duplicate case values are illegal.
• C: Even the last default block typically uses break or returns; D is the clearly correct general statement.
• E: No implicit fall-through in non-empty cases.

Common Pitfalls:
Confusing C# switch rules with C/C++ behavior.

Final Answer:
The if statement selects a statement for execution based on the value of a Boolean expression.