Show a note to customer conditionally if he selects a specific size of the product | Magento 2

I would like to show the customer a note based on the size he chooses in the configurable product page.
For example I got bed sizes options from 120×200 to 200×200 and these are shown as a select dropdown.
I want to show a custom text note under select dropdown only if the customer chooses a size between 120×200 and 160×200.