4. (12 marks) For each of the histories shown in Figs. 2 and 3, are they sequentially consistent? Linearizable? Justify your answer. .write(0 .read write(2) r.write(1) r.read(2) rread(2) r.write(3) Fig. 2 History (a) r.read(1) r.write(1) r.read(2) r.write(2) r.read(1) Fig. 3 History (b) 4. (12 marks) For each of the histories shown in Figs. 2 and 3, are they sequentially consistent? Linearizable? Justify your answer. .write(0 .read write(2) r.write(1) r.read(2) rread(2) r.write(3) Fig. 2 History (a) r.read(1) r.write(1) r.read(2) r.write(2) r.read(1) Fig. 3 History (b)