(in advance) in a highly magnetized material, all or most of the magnetic domains are arranged a) in a x-shape b) in the same direction c) in different directions d) in a circular path like a circuit

Consider a production line with five stations. station 1 can produce a unit in 9 minutes. station 2 can produce a unit in 10 minutes. station 3 has two identical machines, each of which can process a unit in 12 minutes (each unit only needs to be processed on one of the two machines. station 4 can produce a unit in 5 minutes. station 5 can produce a unit in 8 minutes. which station is the bottleneck station?