4. Which of the following levels involve no customization?a) Make-to-Stockb) Make-to-Orderc) Assemble-to-Orderd) Engineer-to-Order

The level that involves no customization is a) Make-to-Stock.

Here's why:

a) Make-to-Stock (MTS) involves producing goods based on demand forecasts. The products are made and stocked in advance. There is no customization involved as the products are made to a standard specification.

b) Make-to-Order (MTO) involves producing goods only after receiving a customer's order. The product is customized according to the customer's specifications.

c) Assemble-to-Order (ATO) involves keeping some parts in stock and only assembling them after receiving a customer's order. The product can be customized at the assembly stage according to the customer's specifications.

d) Engineer-to-Order (ETO) involves designing and producing goods only after receiving a customer's order. The product is highly customized according to the customer's specifications.