I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "During World War II, the islands were used as a top secret Royal Navy weather and radio station codenamed HMS Atlantic Isle, to monitor Nazi U-boats (which were required to maintain radio contact) and shipping movements in the South Atlantic Ocean. The first Administrator, Surgeon Lieutenant Commander E.J.S. Woolley, was appointed by the British government during this time."? 

What was being monitored communicated via?