Correct option is B
To solve this problem, we use the formula for capillary rise:h=ρgd4σcosθWhere:h=capillary rise=6mm=0.006mσ=0.08N/m (surface tension)ρ=900kg/m3 (density of the liquid)g=9.81m/s2 (acceleration due to gravity)θ=0∘=>cosθ=1d=Diameter of the capillary tubeRearranging the formula to find d:d=ρgh4σcosθd=900×9.81×0.0064×0.08×1d=6.04mm