Which of the following is not a service design technique used to reduce cost?

A) increasing customer interaction
B) delaying customization
C) automation
D) modularizing the product
E) reducing customer interaction

Increasing customer interaction is likely to increase the cost of service, as it requires more resources such as staff, time, and potentially new technology. The other options listed are service design techniques that can reduce cost: delaying customization reduces the need for additional resources and specialization, automation reduces the need for human labor, and modularizing the product can lead to greater efficiency and cost savings in production and delivery. Reducing customer interaction can also reduce costs, but it is not the best answer in this case as it is not the only option that does not reduce costs.