Think you can just pick one brand and try ... since it really depends on whether baby works on a particular brand. Those which works on one baby may not work on another.
你的小朋友食那個stage (#1, #2, #3), my daughter is 21 months old,當她開始食米飯后,便便很硬,有時更要用甘油條,我都有想到是A+3的問題,但有天只食A+3沒有食白飯(off-course together with other dishes), 大便OK, 你的情況是否這樣?