Smooth fm radio uses a approach when it mixes pre-recorded local segments with its national music blocks.

mass customization approach.

Explanation:

Mass customization approach can be defined as an approach in which a customer can pursue the company to modify certain elements in the product, in a low cost. Mass customization is also known as build-to-order or made-to-order technique.

The approach that the Smooth FM radio has used in the given case is mass customization approach. As defined above, mass customization helps to modify elements in a product with low-cost involvement, Smooth FM has modified or mixed pre-recorded local segments with its national music blocks,

This modification of products is an example of build-to-order or mass customization technique.

So, the correct answer is mass customization approach.