Answer:
Category D
Explanation:
In the USA, the Federal Animal Welfare Regulations require that research laboratories report animal use according to the species as well as the number of individuals subject to experimentation procedures. Moreover, animal use for research/teaching purposes is also reported according to the classification by pain and distress categories. Basically, this classification has four categories (B,C, D and E) in increasing order according to the pain level suffered by research animals. Animals within Category D include those subjected to potentially painful or stressful procedures. In consequence, in this category, it is imperative the utilization of proper anesthetics and/or analgesics in order to diminish the pain and suffering of these animals at the lower level possible.
