Taste buds were the primary tool early humans used for testing foods. Sour taste warns of possible spoilage of food while bitterness is a warning of many poisons. Early humans also recognized sweet foods and salty foods as meeting nutritional needs. So the fact that people can now clearly distinguish these four tastes-sour, bitter, sweet, and salty-is completely explained by people' s use of taste to test for the healthfulness of foods. The reasoning in the argument is most vulnerable to criticism on the grounds that the argument
A: takes a necessary condition for the truth of its conclusion to be sufficient to justify that conclusion
B: takes what might be only a partial explanation of a phenomenon to be the complete explanation
C: fails to consider that many people associate foods more with their smells than with their tastes
D: fails to consider that some nutritious foods are bitter when raw but not after being cooked
Choose A, B, C or D as your solution.
B