Which concessive clause cannot be found in this text?

e did have a wiffle-ball set, but you would have been hard-pressed to find it in our playroom.|I'm not denying that most little girls love dolls and most little boys love video gamdes....|Hard as he works, he still cannot pull his grades up.|It may be true that some people favor the right side of their brain and others the left.But how relevant is that to me or to anyone as an individual?