Final answer:
The diffusion of responsibility theory indicates that the presence of more bystanders reduces the likelihood of any one person helping, pointing to 'C) The number of other bystanders at the scene' as the right answer.
Step-by-step explanation:
According to the diffusion of responsibility theory, the biggest factor in predicting whether or not a bystander will help someone in need is the number of other bystanders at the scene.
This is rooted in the bystander effect, which suggests that people are less likely to take action or help in an emergency when there are others present.
The responsibility to help feels less personal and more distributed, leading to lower chances that any one individual will intervene. Hence, the correct answer to the question would be (C) The number of other bystanders at the scene.