Identify the Systems Constraints$/$Bottleneck$($s$)($BN$).$ All of the following were used by Alex to identify the Systems BN$\text{'}$s except,

Question $5$ options:

inventory was building$-$up in front of some processes

processes that made specific parts that were always in short supply

finding the processes that were always idle

finding the parts that other processes were always waiting on

a and b