Consider the following sequences of operation requests (i.e. T1, T2, T3, T4) from transaction 1, 2, and 3. ri (X) represents that transaction i requests to read object X. wi (X) represents that transaction i requests to write object X. Classify these sequences into strict, cascadeless, recoverable, or nonrecoverable:

T1: r1(A); r3(A); r1(B); r2(B); r2(C); r3(C); w2(B); w1(A); w3(C); c3; w2(C); c2; c1; T2: r1(A); r1(B); r2(B); r3(A); r3(C); w1(A); c1; w3(C); c3; r2(C); w2(B); w2(C); c2 T3: r2(B); r3(A); r2(C); r3(C); w2(B); w3(C); w2(C); r1(A); r1(B); w1(A); c1; c2; c3; T4: r1(A); r1(B); r2(B); w1(A); c1; r2(C); r3(A); r3(C); w2(B); w2(C); c2; w3(C); c3 (Please only answer if you are completely sure about it)