Benign hyperplasia (excessive growth of cells) of which pa of the male reproductive system would be most likely to interfere with the passage of urine?

Remember that the prostatic urethra travels through the prostate gland. So, if the periurethral zone of the prostate hyperophied, the nearby prostatic urethra would be occluded. The central and peripheral zones of the prostate are not as close to the urethra. If they enlarged, they would not restrict the flow of urine quite as much. The ejaculatory duct is the duct formed once the ductus deferens joins with the duct of the seminal vesicle. It passes through the prostate gland, but its enlargement would have no effect on the prostate or the urethra. Ref: La Rochelle J., Shuch B., Belldegrun A. (2010). Chapter 40. Urology. In F.C. Brunicardi, D.K. Andersen, T.R. Billiar, D.L. Dunn, J.G. Hunter, J.B. Matthews, R.E. Pollock (Eds), Schwaz's Principles of Surgery, 9e.