Consider the following database schedule with two transactions, T_{1} and T_{2}.

S = r_{2}(X); r_{1}(X); r_{2}(Y); w_{1}(X); r_{1}(Y); w_{2}(X); a_{1}; a_{2}

where r_{i}(Z) denotes a read operation by transaction T; on a variable Z, w_{i};(Z) denotes a write operation by T_{i} on a variable Z and a, denotes an abort by transaction T_{i}.

Which one of the following statements about the above schedule is TRUE?

(A) S is non-recoverable

(B) S is recoverable, but has a cascading abort

(C) S does not have a cascading abort

(D) S is strict