Final answer:
Statement A is false; strategic planning is structured, not unstructured, and focuses on setting long-term goals for an organization.
Step-by-step explanation:
The question relates to the different aspects of planning and management within a firm. Examining the provided statements, Strategic planning is known for its structured approach to setting long-term goals and directions for an organization, contrary to the assertion that it is relatively unstructured, thus making Statement A false. Strategic planning indeed involves substantial external information, aligning with the implication of Statement B. Statement C correctly identifies that tactical management pertains to ensuring the effectiveness of operations within different units of a company and may involve some external information. Finally, Statement D is accurate when it suggests that tactical management utilizes highly detailed and precise data to make short-term decisions.