Virtual method behavior when not overridden in a derived class — choose the correct statement.

Introduction / Context:
Understanding default virtual method behavior is key to predicting runtime dispatch in C#.

Given Data / Assumptions:

• We have a base class with a virtual member.
• The derived class may or may not override it.

Concept / Approach:
If the derived class does not provide an override, the base virtual implementation is used for calls, including those made through base references.

Why Other Options Are Wrong:

• A: Abstract classes cannot be instantiated at all.
• B: Methods are non-virtual by default unless marked virtual/abstract/override.
• D: Omitting override does not auto-override; it either hides (with new) or just defines a separate member.
• E: Derived classes can provide their own overrides.

Final Answer:
If a derived class does not override a virtual method, the base class implementation is used.