An assembly line is designed as depicted in the picture. There are two lines performing different operations and both lines are required for all units $($In other words, incoming units need to undergo operations in both parallel lines$).$ One of the two lines $($the one on the top$)$ has two stations A and B on it$.$ The other line $($the one on the bottom$)$ has one station C$.$ For any incoming unit, the operations at both parallel lines start together at the satine time and are performed concurrently. To start the operation at station D$,$ the operation in both lines should be completed for that unit. Considering the process times given in the flow chart, specify the bottleneck$($s$).$

Note:

$1-$ These are checkboxes, you can select more than one option if required.

Station A

Station B

Station C