Consider a database DB with relations R1 and R2. The relation R1 contains tuples t1 and t2 and the relation R2 contains tuples t3, t4, and t5. Assume that the database DB, relations, and tuples form a hierarchy of lockable database elements. Explain the sequence of lock requests and the response of the locking scheduler to the following schedule. You may assume all lock requests occur just before they are needed, and all unlocks occur at the end of the transaction, i.e., EOT.

T1:R(t1), T2:W(t2), T2:R(t3), T1:W(t4)