Subject: mathqa
Question: in triangle pqr , the angle q = 90 degree , pq = 5 cm , qr = 8 cm . x is a variable point on pq . the line through x parallel to qr , intersects pr at y and the line through y , parallel to pq , intersects qr at z . find the least possible length of xz
Option: 
A: 3.6 cm
B: 3.2 cm
C: 4.0 cm
D: 2.4 cm
Answer: C