I'm not sure how you could do that with a single question like that. You could try it as three similar select_one questions: use the same choice list, with the labels/hint text explaining "Pick the 2nd most important issue" etc. Then use constraints like not(selected(${Question2}, ${Question1})) and not(selected(${Question2}, ${Question3})) to keep the user from selecting the same answer each time.
Alternatively, you could have seven integer questions (one question for each issue), prompting the user to input a value of 1 through 3 next to different questions to rank them. This would require more work to control, but is still doable. Use similar constraints as above to avoid repeat values (this will be longer because you're comparing to six other questions), as well as adding and .>0 and .<4 to the constraint to keep the range between 1 and 3. Then a final calculation question that calculates the sum of the seven questions and ensures it equals 5, to make sure the user didn't rank less than three issues.
It kinda depends on how you want to use the data in your database or reports, and what would make the most sense for the user filling out the form.
