You have 5 thermocouples that are designed with different diameters which have 1s, 2s, 3s, 4s and 5s as their time constants respectively. You are using a thermocouple as the feedback sensor to a first-order flow-controlled temperature process. The response times of the controller and the process are 5s and 20s respectively. If your process has a safety requirement of 41s response time, what is the slowest responding thermocouple that you will choose?