Klarna checkout: Where to place the following code to fire the impression?

Since Klarna has inadequate documentation on refreshing placements, I seek help from SO in understanding where to place the following code to ensure the price gets refreshed in the Klarna placement as the customer chooses a variant of a configurable produt.

window.KlarnaOnsiteService = window.KlarnaOnsiteService || []
  eventName: 'placement-impression',
  placementKey: 'credit-promotion-badge'

Code snippet below is placed in the phtml file from product details page.