C++ static members: which statements about static data and static member functions are correct?

Introduction / Context:
Static members in C++ belong to the class itself rather than to any individual object. Understanding their access rules and lifetime is critical for designing shared counters, cached state, or class-wide configuration. This question asks which statements accurately describe static data members and static member functions.

Given Data / Assumptions:

• Static data members have a single storage location shared by all instances.
• Static member functions do not have a this pointer.
• Access from outside typically uses ClassName::member syntax.

Concept / Approach:

A static member function lacks the implicit object pointer (this), so it cannot access non-static members directly because those require an object. It can, however, access static data members. A static data member is indeed shared across all objects. While you can access a public static data member “from main” using ClassName::member (or through an object), the option’s wording “directly” is ambiguous. Therefore, the best precise choice among the provided options is “Both A and B.”

Step-by-Step Solution:

Verification / Alternative check:

Write a small program with a class counter and a static incrementor(). Attempting to read a non-static field from a static function without an object fails to compile. Accessing the static field as ClassName::counter works as expected.

Why Other Options Are Wrong:

C alone overstates “direct” access without clarifying syntax and access level.

A or B alone omit the other equally correct fact.

Common Pitfalls:

• Trying to use this in a static member function.
• Forgetting to define the static data member outside the class (pre-C++17) or using inline variables (C++17+) appropriately.

Final Answer:

Both A and B.