Suppose you have a column that is not a primary key column, but you want to ensure that there are no duplicate values, such as a student ID$.$ Which word can you add to the column declaration to ensure that duplicate entries will cause an error?

Suppose you have a column that is not a primary key column, but you want to ensure that there are no duplicate values, such as a student ID$.$ Which word can you add to the column declaration to ensure that duplicate entries will cause an error?

Single

Unique

Distinct

Unusual