Hello!
Given the units of measure, we can determine the use of ounces, liters, grams, and milliliters in everyday life. Remember that in Guatemala, they used the metric system.
Ounces are a unit of mass, weight, or volume, and it is not used in the metric system.
Liters are used to measure volume, and therefore, it can not be used.
Grams are used to measure the weight, and is apart of the metric system.
Milliliters are also used to measure volume, and therefore, it also can not be used.
Hence, the answer is grams. Guatemalans typically use grams to measure the weight of flour.