Why did clark hull use k for incentive?

Clark Hull used the letter "K" to represent incentive in his behavioral theory to denote the concept of motivation or drive. In his mathematical formulations, "K" served as a variable to quantify the strength of the incentive that influences behavior, particularly in terms of how it motivates an organism to achieve goals. By incorporating "K," Hull aimed to create a more systematic and empirical approach to understanding the relationship between motivation and behavior.