please answer clearly and explain

C\&A makes two types of products using four machines from 9 a.m. to 5 p.m. each day. Product A visits machines 1,2 , and 4 . Product 8 only visits machines 1 and 3 . The capacity is 0.4 unit per minute at machine 1,0.12 unit per minute at machine 2,0.2 unit per minute at machine 3 , and 0.3 unit per minute at machine 4 . The demand per day is 40 units for Product A and 160 units for Product B. Which resource is the bottleneck? Multiple Choice Machine 1 Machine 3 Machine 2 Machine 4