The correct option (A) (R/2)
Explanation:
Converting left half delta to star
hence R will change to (R/3)
circuit can be drawn as
Hence equivalent resistance between A & B is Req =
Req = R || [(R/3) + {(4R/3) || (4R/3)}]
= R || [(R/3) + (2R/3)]
= R || R
Req = (R/2)
