You can combine the ________ constraint with the sparse index to filter these null values from the unique index and avoid the error.

You can combine the ________ constraint with the sparse index to filte

1.	You can combine the ________ constraint with the sparse index to filter these null values from the unique index and avoid the error.
A.	Hashed
B.	Unique
C.	sparse
D.	compound
Answer» D. compound