The appropriate answer is c. geysers. A geysers a hot water fountain that spouts intermittently with great force, frequently accompanied by a thunderous roar. The world famous Old Faithful is located in Yellowstone National Park. This geyser erupts every 65 min sending a jet of water almost 60 meters into the air. Sinkholes and caves are formed by the action of groundwater on carbonate rocks which causes them to colapse and former these structures.
Your answer is B.
The relationship between medium temperature and speed of sound is a direct relationship: when one factor increases, the other increases as is shown in graph B. The British would choose the the time of day which would give the lowest speed of sound, because this would be easiest to break. Graph B shows that the lowest speed of sound would occur with the lowest air temperature - in the morning.