Answer: C - Competitiveness
Explanation: What is dark triad? It refers to a related personality trait which are: narcissism, machiavellianism and psychopathy and how they relate to the work environment and how co workers relate with each other.
1. Narcissism - These set of people can be selfish, arrogant and boastful
2. Machiavellianism - These set of people can be manipulative, lack emotions and love self interest.
3. Psychopathy - These set of people lack remorse, empathy and are manipulative.
From the explanation above, we can see that the dark triad traits tends to decrease the motivation of workers to work but brings up strive in the workplace environment.