Final answer:
Communications is one of the core capabilities that span all mission areas, essential in various fields such as engineering, foreign policy, and scientific research.
Step-by-step explanation:
One of the three core capabilities that span all mission areas is B) Communications. Effective communication is essential across a wide variety of fields, including engineering, foreign policy, and military planning. It plays a vital role in establishing and maintaining positive relationships, both internally and externally. In the context of international relations, strong communication skills are fundamental to executing the goals of U.S. foreign policy, which include keeping the country safe, securing access to foreign markets, and protecting human rights. In the military sector, communication is critical for strategic planning and operations. For scientists and engineers, communication is necessary to explain the value of their work, secure funding, and contribute to industry advancements, as highlighted in the example of a particle physicist needing to justify their research project.