Q. What is the primary difference between module_function and extend self in Ruby?

• (A) module_function makes the specified methods accessible as module methods, while extend self makes them accessible as instance methods
• (B) module_function makes the specified methods private, while extend self makes them public
• (C) module_function creates a new module, while extend self extends the current module
• (D) module_function makes the specified methods singleton methods, while extend self makes them instance methods