Which of these mammals is not venomous?

The only non-venomous mammal from the list is the bandicoot. It's a mainly insectivorous marsupial native to Australia and New Guinea. Most bandicoots have a characteristic shape: a plump, arch-backed body with a long, delicately tapering snout, very large upright ears, relatively long, thin legs, and a thin tail.

Slow lorises are a group of several species of nocturnal strepsirrhine primates that make up the genus Nycticebus. They are found in Southeast Asia. Slow lorises are accepted as the only known venomous primate. Slow loris venom was known in folklore in their host countries throughout southeast Asia for centuries.

The platypus, sometimes referred to as the duck-billed platypus, is a semiaquatic egg-laying mammal endemic to eastern Australia, including Tasmania. It is one of the few species of venomous mammals, as the male platypus has a spur on the hind foot that delivers a venom capable of causing severe pain to humans.

Solenodons (meaning "slotted-tooth") are venomous, nocturnal, burrowing, insectivorous mammals belonging to the family Solenodontidae. Solenodons have a few unusual traits, one of them being the position of the two teats on the female, almost on the buttocks of the animal, and another being the venomous saliva that flows from modified salivary glands in the mandible through grooves on the second lower incisors ("solenodon" derives from the Greek "grooved tooth").