The nature of planning changes with the level of management. High-level managers deal with long-term planning, whereas low-level managers plan for the short term. However, this does not necessarily mean that middle-level managers do not deal with long- or short-term planning, or low-level managers do not deal with medium-term planning. In fact, they do. Middle-level managers also plan for the long term and short term, but their planning is dominantly for the medium-term. By the same token, low-level managers also plan with different time horizons, but mainly plan for the short term. The correct answer is A.