Each of 9 sides of frame ACDEFB has resistance R (Nine in all). A current I enters at A and leaves at B. Choose the correct alternatives.

A

Currents in branches CD and EF are zero

B

Effective resistance between A and B is $$\frac{4R}{11} I$$

C

Effective resistance between A and B is $$\frac{15R}{11}$$

D

Effective resistance between A and B is $$\frac{3}{4}$$