b) This question tests your understanding of the two-phase transaction commit protocol. The figures below show three situations during protocol execution that involves four processes (one co-ordinator, C, and three servers, S1, S2, S3). For each of the three cases described below, state the final outcome for the transaction (commit or abort), and indicate how each server arrives at that outcome. Assume that a crashed node eventually recovers. no OS1 yes. S2 S1 commit OS2 C commit S3 S3 (i) yes O si yes. S2 ves S3 (i) Fig. (i): In phase one, the three servers respond to the co- ordinator as shown. Then S2 crashes before it receives the decision from the co-ordinator. (ii) Fig. (ii): In phase two, the co-ordinator has decided to commit, and starts sending the commit decision to the servers; it crashes before sending it to S3. (iii) Fig. (iii): In phase one, all the three servers respond as shown; the co-ordinator however crashes and does not receive these messages