In the given figure, AD∥BE∥CF and AB=BC. The ratio of BE:(AD+CF)=
1:2
(i)Join DC to meet EB at P
In△ACD
(ii) B is mid point of AC (given)
BP∥AD (given)
(iii)∴ P is mid point of DC (Converse of mid point theorem)
(iv) Also BP=12AD (mid-point theorem)
In △DCF
(v) P is mid-point of DC (from (iii))
(vi) PE∥CF (given)
(vii) ∴ E is mid-point of DF(Converse of mid-point theorem)
(viii) ∴PE=12CF (mid-point theorem)
(ix) BE=BP+PE
BE=12AD++12CF
BE=12(AD+CF)
∴BEAD+CF=12
BE:(AD+CF)=1:2
Hence (B)