Relation R has schema:

CREATE TABLE R $($

a INT PRIMARY KEY,

b INT DEFAULT $0,$

c INT NOT NULL

$)$;

R is currently empty. Develop a test that determines whether an insertion into R is currently legal. Then apply your test to determine which of the following INSERT statements is allowable.

Question $5$ options:

INSERT INTO R$($c$)$ VALUES$(0)$;

INSERT INTO R$($a$,$b$)$ VALUES$(1,2)$;

INSERT INTO R$($a$)$ VALUES$(10)$;

INSERT INTO R VALUES$(1,1,1)$;