After dehelmintization, a 35-year-old man passed a 3.5 m tapeworm during a bowel movement. A stool examination reveals scolex with four suckers and hooks. Mature proglottids are static with up to 12 primary uterine branches. Which of the following is the most likely diagnosis?

Taeniasis
Diphyllobothriasis
Opisthorchiasis
Echinococcosis