Which of the following commands drops any columns marked as unused from the SECUSTOMERORDERS table? a. DROP

Question:

Which of the following commands drops any columns marked as unused from the SECUSTOMERORDERS table?
a. DROP COLUMN FROM secustomerorders WHERE column_status = UNUSED;
b. ALTER TABLE secustomerorders DROP UNUSED COLUMNS;
c. ALTER TABLE secustomerorders DROP (unused);
d. DROP UNUSED COLUMNS;