Region 1<img src="https://static.zxtiku.com/wangke/imgs/topic/89c8c18abc2e9bbc93845e04b2d86e37.jpg"/> is a dielectric with relative permittivity<img src="https://static.zxtiku.com/wangke/imgs/topic/fb4d68e92ed01648a2473b3813bfc91d.jpg"/>, while region 2 <img src="https://static.zxtiku.com/wangke/imgs/topic/4f6fbca020bab548cd9ce7ee09808558.jpg"/> has relative permittivity <img src="https://static.zxtiku.com/wangke/imgs/topic/8e0186c8aa06ee87fcd3343ffcb31556.jpg"/>. Let <img src="https://static.zxtiku.com/wangke/imgs/topic/c90d84ddadf000ab138c95b507b5522f.jpg"/>, and find <img src="https://static.zxtiku.com/wangke/imgs/topic/726ece9caea61eca4409de66affa3459.jpg"/>.<br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/ffd705e62a26689147c688a20a2e9cfe.jpg"/><br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/420b14ac1e9bb68d02738edaf9fb06cd.jpg"/><img src="https://static.zxtiku.com/wangke/imgs/topic/bd4db38e41bc7b0df7d4679c66ba3a37.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/d2bb5c41fed8440c62872529b32dc625.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/aa86b587597c8d293ab797c578ca48ad.jpg"/>