challenge: What is the primary focus of the Program Executive Office, Unmanned and Small Combatants (PEO USC)?
  
  A. Development of advanced naval communication systems
  B. Design, development, build, maintenance, and modernization of unmanned maritime systems, mine warfare systems, and small surface combatants
  C. Procurement and management of naval aircraft carriers
  D. Design, development, and maintenance of nuclear submarines
  Answer: 