Which of these associations is mismatched? a. interstitial cells - testosterone b. seminiferous tubules-sperm production c. vasa deferentia-seminal fluid production d. urethra-conducts sperm

In this step, we'll look at each option and analyze whether the association is correctly matched or not. a. interstitial cells - testosterone Interstitial cells, also known as Leydig cells, are indeed associated with testosterone production. b. seminiferous tubules-sperm production Seminiferous tubules are the site where sperm is produced, so this association is also correct. c. vasa deferentia-seminal fluid production Vasa deferentia, also known as ductus deferens, transport sperm from the epididymis to the ejaculatory ducts but are not responsible for seminal fluid production. d. urethra-conducts sperm The urethra, a tube that runs through the penis, does conduct sperm towards the exterior during ejaculation; thus, the association is correct.

As per our analysis in Step 1, option c is the mismatched association. The vasa deferentia are involved in sperm transportation rather than seminal fluid production.

Among the given options, the mismatched association is option c: vasa deferentia - seminal fluid production.