In SQL Server, which one of the following operations applied on a database item X do not conflict in a schedule? (r and r2 are read operations for transaction T1 and T2 respectively. w1 and w2 are write operations for transaction T1 and T2 respectively.)

a. r1(X) and w2(X)
b. w1(X) and w2 (X)
C. r1(X) and w1(X)
d. r2(X) and w1(X)

c. r1(X) and w1(X)