Premise: Employees who understand how their roles fit into the "big picture" of a business or organization are more motivated to do their jobs well.

Conclusion: Corporate leaders wishing to improve workers morale should thus consider the "participatory" style of management, in which workers are given an individual piece of a project to carry out, replete with its own explicit goals and responsibilities.

let's find the assumption underlying this statement.

Option A - Incorrect:
Well, this claim is not in compliance with the passage's expression. Workers who are motivated to do their jobs are those who understand how their roles fit into the 'big picture' of a business or organization, and not those filled with responsibilities.

Option B - Incorrect:
This claim cannot be proved from the passage above. Therefore, it is incorrect.

Option C - Incorrect:
This passage is not to compare the effective leadership methods between managers who use a less interactive leadership approach and those who do use such methods.

Option D - Correct:
This claim "having responsibility for a segment of an enterprise helps employees grasp where they fit within an organizational structure" validates the passage statement "Employees who understand how their roles fit into the "big picture" of a business or organization are more motivated to do their jobs well." Hence, this option gives the best assumption for this passage.

Option E - Incorrect:
This claim is irrelevant to the recommendation given to corporate leaders in the passage, which is, "Corporate leaders wishing to improve workers morale should thus consider the "participatory" style of management, in which workers are given an individual piece of a project to carry out, replete with its own explicit goals and responsibilities."