If it is center only-option, I would probably opt for row 2, 4 or 6 (forward facing). But if you are talking QR706 on 3/2, you may be limited to “whatever is available.” (ExpertFlyer is showing only one seat available)

Also, you may need to call to get a center section seat assigned to you. For single-passenger reservations, these are often blocked for online selection as they are prioritized for couples/families.