iii$)$ In the below example, a Flight transfer transaction $($between flights $\backslash ($ X $\backslash )$ and $\backslash ($ Y $\backslash ))$ and a Flight reservation $($flight $\backslash ($ X $\backslash )$ only$)$ transaction are being carried out simultaneously on the same database. The flight transfer transaction fails after reading data item reserved$\_$seats$\_$Y$.$ Explain the type of error that will occur in this case.

$[9$ marks$]$