Final answer:
The trait that was not characteristic of the mystery religions is the worship of multiple gods, as they typically focused on a single deity. By contrast, Christianity's emphasis on monotheism significantly differentiated it from these cults.
Step-by-step explanation:
The traits of the mystery religions did include secret rituals, a belief in an afterlife, and an emphasis on personal salvation. However, the incorrect trait among the options provided is the worship of multiple gods. Mystery cults were typically devoted to a single deity, setting them apart from the broader Greco-Roman tradition of polytheism. For example, the followers of the cult of Mithras worshipped Mithras to the neglect of other Roman gods. Moreover, mystery cults had hierarchical levels of initiation and were not as interested in the afterlife as previously thought. In contrast, early Christianity's foundation in monotheism was a critical departure from these traditions. The Christian rejection of civic cults due to monotheistic beliefs eventually led to persecution, further highlighting the difference between mystery cults that allowed for adoration of several deities and the strictly monotheistic nature of Christianity.