Leela and Issac have identical bags. One day, at school, their bags get exchanged.
How does Leela know that it is not her bag without opening it?

The correct option is B Her bag has 3 compartments.
The table below shows the features of Leela's and Issac's bags as well as some common features.

The features that are present only in Issac's bag and not in Leela's bag are:
(i) Issac's bag has a mobile pouch.
(ii) Issac's bag has 3 compartments.

Thus, Leela can know that the bag having three compartments is not her bag.