Oral surgeon put his finger on the nose of the Pt. and ask him to blow this done to check.. Posterior (distal) extension of posterior palatal seal - vibrating line

Oral surgeon put his finger on the nose of the Pt. and ask him to blow this done to check?
A. Anterior extension of posterior palatal seal
B. Lateral extension of posterior palatal seal
C. Posterior (distal) extension of posterior palatal seal (vibrating line)***
D. Glandular opening.