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so basically it's between primary benzylic carbocation which is known to be stable (benzlic) and secondary carbocation which is allylic... which is also stablized by resonance, i know that usually benzylic is more stable than allylic but when they are same degree.. here its different...

any help? enter image description here

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The tropylium carbocation (the one on the right) is more stable than the primary benzylic carbocation because it is not only resonance stabilised but also quasi-aromatic (which means that the charge is a part of the aromaticity) which greatly increases the stability of the cation. In contrast, the benzylic carbocation is aromatic but the positive charge is not a part of the aromaticity so it is not stabilised that much.

Hope it helps!

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