Final answer:
The upper limit for osmolality of infant formulas to avoid tolerance issues is around 280 to 300 mOsm/kg, with the most suitable choice being 360 mOsm/kg.
Step-by-step explanation:
The upper limit for the osmolality of infant formulas to avoid tolerance issues is typically around 280 to 300 mOsm/kg. This is because body fluids are often maintained within this range, providing optimal hydration and nutrient balance.
Therefore, options 460 mOsm/kg, 560 mOsm/kg are far too high, and would pose a risk for infants. While 260 mOsm/kg is close to the range identified, it is on the lower end and may not represent an upper limit. The most suitable choice is 360 mOsm/kg, which is close to the upper range of body fluid osmolality yet still below the threshold that may cause tolerance issues.