题目1单选题
图示电路中a、b端的等效电阻<img src="https://tihai-oss-cloud.itihey.com/img/615ca7e970085c87caca723c68e6f4a7.png">为 答( ) <img src="https://tihai-oss-cloud.itihey.com/img/98b710a3214e39ea3d7a07f468095123.png">A. <img src="https://tihai-oss-cloud.itihey.com/img/967137ae6d4ae91b17b3b50f8241e670.png">B. <img src="https://tihai-oss-cloud.itihey.com/img/312704c24962b6ac7fad8321f8d4c58b.png">C. <img src="https://tihai-oss-cloud.itihey.com/img/24dc5e85482d20110d4a7be989ad7530.png">D. <img src="https://tihai-oss-cloud.itihey.com/img/63e172e65622d08a7b8215410c852bd5.png">