Final answer:
The question of least pertinence is 'What is the child's favorite color?' when questioning the parent of a child who ingested a poisonous substance.
Step-by-step explanation:
The question is asking which of the following questions would be of least pertinence when questioning the parent of a child who ingested a poisonous substance.
The question options are:
- What is the child's age?
- What is the child's weight?
- What is the child's favorite color?
- What is the child's blood type?
The question of least pertinence is 3) What is the child's favorite color? The child's favorite color does not provide any relevant information to assess the situation of ingesting a poisonous substance.