When does a dangling pointer occur?

A dangling pointer occurs when a pointer continues to reference memory that has been deallocated or is no longer valid. This happens when a dynamic memory block is freed but the pointer variable is not set to null, or when a pointer references a local variable that goes out of scope. Option B describes an uninitialized pointer (not dangling), Option A is incorrect because static local variables persist for the program lifetime, and Option D incompletely describes the problem—it's not the act of freeing that creates the dangling pointer, but the pointer's continued use afterward.

Step-by-step Derivation:
Key scenarios for dangling pointers:

1. Use-after-free: int *p = new int(5); delete p; *p = 10; // p is now dangling
2. Returning address of local variable: int* func() { int x = 5; return &x; } // dangling after function returns
3. Pointer to freed stack memory: Accessing a pointer after its referent goes out of scope

Uninitialized pointers (B) point to random addresses but are not inherently "dangling" in the technical sense. A dangling pointer specifically points to memory that was once valid but is now invalid.