The correct option is C No, it is π d.
Given−d=diameterofawheel.Tofindout−Thestatement,thatthedistanceDtravelledbythecircularwheelinonerevolution=2πd,istrueornot.Solution−d=2r=diameterofawheelwhenristheradiusofthewheel.∴Thecicumferenceofthewheel=2πr.WeknowthatthedistanceDtravelledbyacircularwheelinonerevolution=thecicumferenceofthewheel.HereD=2πr=πd.∴ThestatementD=2πdisnotcorrect.Ans−OptionC.