What is the output of the following piece of code? class stud: ‘Base class for all students’ def __init__(self, roll_no, grade): self.roll_no = roll_no self.grade = grade def display (self): print("Roll no : ", self.roll_no, ", Grade: ", self.grade) print(student.__doc__)

• A. Exception is thrown
• B. __main__
• C. Nothing is displayed
• D. Base class for all students