The correct option is A 21 cm
Perimeter of regular hexagon
= 1 m 26 cm
= 126 cm (1 m=100 cm)
Number of sides in regular hexagon
= 6
Since, perimeter of regular hexagon
= 6× Length of Side
So, Length of a side of regular hexagon
= Perimeter of regular hexagon6
= 1266 cm
= 21 cm
Therefore, length of a side of regular polygon is 21 cm.
Hence, (b) is correct.