Consider integers p, q, r such that |p| < |q| < |r| < 40 and p + q + r = 20. What is the maximum possible value of pqr?
A. 3600
B. 3610
C. 3510
D. 3500
E. 4000
A. 3600
B. 3610
C. 3510
D. 3500
E. 4000