$3.[$CLO $2\mathrm{.}3S1$

a$.$ Suppose you registered a wrong course to your timetable and the transaction committed, what can you do to correct this issue, and verify your answer?

b$.$ Based on the following recovery timeline to illustrate the effect of checkpointing. Specifiy what will the system do with each transaction.

T$3T_3{|}_{\text{B}\text{E}\text{G}\text{I}\text{N}}^{\text{R}\text{E}\text{A}\text{D}(C)\text{W}\text{R}\text{T}\text{E}\text{B}}|$