Here it is
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In hyperconjugation, H on  the adjacent C gives its sigma bonded electrons which results in new pi bond between adjacent carbon and already sp2 carbon atoms.
If you carefully observe then except structure 1 ,rest all have H and sigma bonded electrons which can come easily in plane of sp2 carbon to make a new pi bond .So hyperconjugation is feasible.
In structure I, one adjacent carbon has no H and another is bridged carbon which can not come in plane of doubly bonded carbons to participate in conjugation.