Final answer:
The characteristic that can be beneficial in small numbers but problematic in excess within a group dynamic is extraversion. The correct answer is option: b) extraversion.
Step-by-step explanation:
The personal characteristic that is generally beneficial to the social climate of a group when possessed by a few members but can lead to power struggles and unproductive conflict when too many members have it is extraversion. Extroverts tend to be sociable, assertive, and enjoy seeking exciting engagements.
A few extroverts can enliven a group's social climate, but an excess can lead to competition for attention and dominance, disrupting group harmony. Characteristics like conscientiousness, agreeableness, and neuroticism have different impacts on group dynamics and individual success, such as conscientious individuals being hardworking and agreeable persons being cooperative.
Extroversion, on the other hand, can clash with a group's collectivist norms, especially in cultures that value collective harmony over individual prominence.