There could certainly be more than one old grandma looking instead of highlighting there is only one by saying the and there is a range of emotions possible.  Angry would be unlikely.


Context: "An old grandma is looking at a woman who is holding a large white tub of food in a crowd of people."
Hypothesis: The grandma is angry with the woman with the tub.
Based on the context, is the hypothesis true, false, or unknown?