• Obstructive Urolithiasis in Goats and Rams:
• Uroliths (struvite, calcium carbonate) travel down the pelvic urethra and sigmoid flexure.
• In male goats and sheep, the distal end of the penis terminates in a narrow, projecting vermiform appendage called the urethral process (filiform appendage).
• Because this process has the narrowest lumen of the entire urinary tract, it is the single most common site for urethral calculi obstruction in bucks and rams. Amputation of the urethral process is often the immediate emergency therapeutic step.
• nalysis:
• (Urethral process): Correct.

Correct option: (3) Urethral process