Queue enumeration — choose the correct code to access all elements of a System.Collections.Queue instance.

Introduction / Context:
All non-generic collections in System.Collections support enumeration via IEnumerable/IEnumerator. Queue is no exception.

Concept / Approach:
Call q.GetEnumerator() to get an IEnumerator. Iterate by calling MoveNext() and reading Current. foreach uses the same pattern behind the scenes.

Why Other Options Are Wrong:
Option B: GetEnumerator() returns IEnumerator, not IEnumerable. Option C: GetEnumerable() does not exist. Option D: GetEnumerator() is an instance, not static, method. Option E: foreach is supported, but explicit IEnumerator use is also valid.

Final Answer:
IEnumerator e = q.GetEnumerator(); while (e.MoveNext()) Console.WriteLine(e.Current);