Answer: d. penis
Step-by-step explanation:
In pigs some of the parts of the excretory system are related to the reproductive system. The urethra is the tube where the urine get collected from the urinary bladder so as to release through the external orifice. The urethra remains connected to the penis. The vas deferens are the tubes which drains the sperms from the testes into the urethra. The urine as well as the sperms are both drained into the urethra which are finally carries away and excreted out from the body by another tube like structure that is penis.