Let us now use a millimeter scale (on which millimeter marks are there). This is also our normal meter scale which we use in our routine life. From the figure, we can see that length AB is more than 3.3 cm and less than 3.4 cm. If we note down the length,
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`l= AB = 3.4cm. `
Then, this measurement has two significant figures 3 and 4 in which 3 is absolutely correct and 4 is reasonably correct (doubtful). Least count of this scale is 0.1 cm because this scale can measure accurately only upto 0.1 cm. Futher, maximum uncertainly or maximum possible error in l can also be 0.1 cm.

Answer

A