Non Verbal Reasoning - Dot Situation - Discussion

In fig. (X), one of the dots lies in the region common to the circle and the triangle only and the other dot lies in the circle alone. In each of the two figures (1) and (2), there is no region common to the circle and the triangle only. In fig. (4) there is no region which lies in the circle alone. Only fig. (3) consists of both the types of regions.