Final answer:
For obtaining a CPL after a PPL, complete instrument rating training is required. This is necessary to teach pilots to fly under IFR conditions, and involves learning to navigate and manage the aircraft using flight instruments.
Step-by-step explanation:
The question pertains to the instrument training required for a Commercial Pilot License (CPL) after obtaining a Private Pilot License (PPL). The correct answer is c) Complete instrument rating training. While holding a PPL the next step to obtain a CPL typically requires a pilot to complete an instrument rating training. This instrument rating is crucial as it teaches pilots to fly under Instrument Flight Rules (IFR) which is essential for flying in a wider range of weather conditions and for flying commercially.
The instrument training focuses on understanding and using flight instruments to safely operate an aircraft without relying on visual references outside the cockpit. Before obtaining a CPL one will have to meet specific instrument training hours and pass an instrument rating practical test. This preparation involves learning how to read and interpret flight instruments navigate using radio aids, and manage the airplane solely by reference to instruments during all phases of flight. It is considered a comprehensive training program that goes beyond basic instrument skills.