【单选题】 A <{p}>It increases the router CPU utilization considerably<{br/}><{/p}> B <{p}>It requires the not standard jumbo MTU<{br/}><{/p}> C <{p}>lt duplicates functionality already present in IPsec<{br/}><{/p}> D <{p}>It does not add any additional level of security<{br/}><{/p}>
