Correct Answer - Option 1 : 2

**Explanation:**

Divide 9 bags into three parts.

2,2 and 5 respectively.

If we compare the 2,2 bags on pans of a balance.

We can identify which side is the lighter bag placed.

And then we will need only one more weighing for identifying the faulty bag.

So only two weighings are required.

**Alternative solution:**

In the case of a weighing balance (i.e. beam balance) the following model can be observed.

1 - 3 → 1 weighing required

4 - 9 → 2 weighings required

10 - 27 → 3 weighings required

28 - 81 → 4 weighings required

And the process will go so on.

**As there are nine objects. The minimum number of weighings required will be only 2.**