factory has the production process shown in the figure. There are five operations in sequence. The product only needs to go through one of the parallel machines in each case where parallel machines exist. What is the bottleneck time per batch of this process?

Proof

Mix

$60$ min.$/$batch

$50$ min$/$batchi

Bake

$60$ min.$/$batch

Pack

$40$ min.$/$batch$/$

Proof

$60$ min.$/$batch

Cut

$35$ min.$/$batch

Mix

$50$ min$/$batch

Bake

Proof

$60$ min.$/$batch

$60$ min.$/$batch

Pack

$40$ min.$/$batch

$$ A$.$

$35$ min.

$60$ min.

$$ c$.30$ min.

$$ D$.$

$20$ min.

E$.$

$50$ min.