Why is D the right answer ? how did they get to that solution?

INTEX limited is an IC manufacturing company. There are 4 steps involved in making the IC are etching, deposition, oxidation and deposition. Each IC starts with the process of etching and ends with the process of deposition. Consider that there is only one station for each process. The number of employees at each station and the time taken to complete the processes is given table below.

Station	Staffing	Process Time(Hours per Chip per Worker)
1 Etching	4	5
2 Deposition	3	3
3 Oxidation	3	2.5
4 Deposition	2	1.6

If the company cross-trains all the employees and installs all the required equipment to perform all the operations involved in making the IC in all the stations, what is the maximum capacity of the process in ICS per hour?

1. 12.1
2. 1.21
3. 39.7
4. 1.00
5. 1.50

Answer: D