Increases in productivity are difficult to achieve if the task is more __________.

The correct choice is personal because productivity improvements are often tied to individual effort, communication, and interpersonal relations. When tasks require personal involvement, such as collaboration, creativity, or nuanced decision-making, it becomes challenging to implement systematic improvements. This is due to the variable nature of personal interactions, which can be influenced by emotions, social dynamics, and differing skill sets.

In contrast, tasks that are mechanical, automated, or structured tend to have more defined processes that can be analyzed and optimized more readily. For instance, mechanical and automated tasks typically follow repetitive, predictable patterns that lend themselves well to efficiency enhancements through technology or process design. Structured tasks have clear guidelines and frameworks that can facilitate the identification of bottlenecks or redundancies, making productivity increases more achievable. However, personal tasks rely on the unique skills and motivations of individuals, making it harder to standardize and improve productivity uniformly.