woocommerce and multi year purchase

Hello
I’m working on a client’s website that uses woocommerce.
They want to have a simple variation in a woocommerce product where the site visitor can buy admission to a given event for a 1, 2, or 3 year period.

what would be the easiest way to add this 1, 2, and 3 year price difference for a given product in woocommerce?

*this can be very simple and does not need to be a full bonafide “membership” where they have login access to a virtual resource for a given time period or anything like that. It simply needs a price difference for the same thing, only with 3 variations on the price.

thanks very much