Vesicoureteral Reflux Occurs in Children Because

Vesicoureteral reflux occurs in children because:

A) they do not ask for help in urinating in a timely manner and urine is forced up into the ureters.
B) the submucosal segment of the ureter is short, making the antireflux mechanism inefficient.
C) the trigone lying between the opening to the ureters and the urethra is underdeveloped.
D) as the bladder in infants and children fill, it pulls the smooth lining of the transitional epithelium away from the ureters so that the reflux valves are ineffective.