How can I put more than one option for an article in a multiple selection?

You can use the multiple choice field and assign value to each option.

1). Multiple choice

2). Assign calculation value https://www.jotform.com/help/301-How-to-Assign-Calculation-Value

3). If you want to pass the total calculation to a payment field, kindly check this guide https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field.

Let us know if you have any questions or if you need further assistance.