The wires `A` and `B` shown in Fig. are made of the same material and have radii `r_(A)` and `r_(B)`, respectively. The block between them has a mass `m`. When the force `F` is `mg//3`, one of the wires breaks. Then
A. `A` will break before `B` if `r_(A)=r_(B)`
B. `A` will break before `B` if `r_(A)lt2r_(B)`
C. either `A` or `B` may break if `r_(A)=2r_(B)`
D. the lengths of `A` and `B` must be known to predict which wire will break.