According to research on the bystander effect, which of the following people is most likely to stop and help a stranger?

a. Jacob is on his way to a doctor’s appointment with his young son.

b. Xavier lives in a crowded city.

c. Malika is in a terrible mood, having just learned that she failed her midterm exam.

d. Ciera just saw a young girl offering her arm to help an older woman cross the street.

e. Mahmood is lost in thought as he walks to work, thinking about his upcoming presentation.