Final answer:
The presence of other bystanders in a situation decreases the likelihood of an individual providing help, due to the bystander effect and diffusion of responsibility. The correct answer is option: b. the presence of other bystanders in the situation.
Step-by-step explanation:
Among the factors provided, the one that does not increase the likelihood of bystanders helping, but rather decreases it, is the presence of other bystanders in the situation. This relates to the bystander effect and the concept of diffusion of responsibility. If there are other people present, individuals may feel less personal responsibility to act because they assume someone else will intervene.
Factors that actually increase the likelihood of helping include feeling good or successful, knowing how to help in the situation, and perceiving the person as deserving of help. These all foster a sense of prosocial behavior, where individuals are motivated to assist others, which is often due to altruism or personal feelings of self-efficacy and competence.