assuming

bd beats sa, wi beats bd and sa beat wi

or

sa beats bd, bd beats wi and wi beat sa

then in this case, all 3 teams get tied with 1 point each. this thing is possible only in pool 2. in pool 1, aus and nz will both crush usa. pool 3, ind and pak will both crush ken and in pool 4, sl will crush both eng and zim.

so with all 3 teams tied, it will come down to nrr and bd will have to maintian a good nrr getting 1 win which is very tough for bd.

so in this case, eithersa or wi get thorugh, but as cricket is a game of uncertainities,so anything can happen any day in cricket. evenbd might sneak through to the semis.