Which of the following statements can be used to change the name of the column name into firstname?

Consider the following table:
mysql> DESC friends;

1 row in set (0.03 sec)
Which of the following statements can be used to change the name of the column name into
firstname?

A.
ALTER TABLE friends CHANGE name firstname VARCHAR(20)

B.
ALTER TABLE friends CHANGE name VARCHAR(20) firstname VARCHAR(20)

C.
ALTER TABLE friends RENAME name TO firstname