Is it permissible to sell an item in installments over a period of one year, two years, or more, while giving the buyer the freedom to choose the duration?

Displaying a commodity with varying prices and payment terms is permissible, provided that one of them is specified at the contracting session, so that the session concludes with a known price and term. However, if the session concludes without definitively selecting one of the prices, and the buyer leaves to choose what suits him from them, this is not permissible, as it falls under the category of "two sales in one."