Three of the Following Tend to Be Fairly Stable Personality

Three of the following tend to be fairly stable personality traits that children have to varying degrees.Which one would psychologists not characterize as a relatively stable personality trait?

A) How often children have negative emotions such as anger or depression
B) How outgoing and friendly children are with their peers
C) How quickly children solve math problems
D) How dependable children are in doing their work carefully and following through on assigned tasks