GATE Computer Science (CS) 2014 Shift 1 Solved Paper

Given the following statements:
S1: A foreign key declaration can always be replaced by an equivalent check assertion in SQL.
S2: Given the table R (a, b, c) where a and b together form the primary key, the following is a valid table definition.
CREATE TABLE S (
                a INTEGER,
                d INTEGER,
                e INTEGER,
                PRIMARY KEY (d)
                FOREIGN KEY (a) references R)
Which one of the following statements is CORRECT?