Which of the following statements are true. l. action and reaction force occur in pair.

II. action and reaction forces act on the same object.

III. action and reaction forces can occur one at a time.

IV. action and reaction forces have the same magnitude.

A. I and II
B. I and IV
C. II and III
D. II and IV

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?