Correct option is D
Let's analyze the relationship between the two events:
Event A: "Ronit went to the dentist."
Event B: "Ronit had a toothache."
Cause-and-Effect Relationship:
Generally, a person visits a dentist because they have a dental issue, such as a toothache.
Event B (Ronit had a toothache) is the cause, and Event A (Ronit went to the dentist) is the effect.
Since the toothache directly led to Ronit's visit to the dentist, Event B is the immediate and principal cause of Event A.
Thus, the correct option is (d) Event A is the effect and Event B is its immediate and principal cause.