Q$10.[$Somewhere in $3\mathrm{.}1$ or $3\mathrm{.}2]$ Which is true?$($only one$)$

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$$ a$.$ Both ESP and AH can be operated in both tunnel or transport mode.

$$ b$.$ ESP works solely in tunnel mode, AH works solely in transport mode.

$$ c$.$ ESP can run in either tunnel or transport mode, but AH only works in tunnel mode.

$$ d$.$ ESP can only run in tunnel mode, but AH can be operated in either mode.