Final answer:
The air mass classification code 'c' indicates a Continental Polar air mass, representing an air mass that forms over land with cold and dry characteristics. Option 4.
Step-by-step explanation:
The air mass classification code "c" indicates Maritime polar air mass. In the context of air mass classification, 'c' represents 'continental' and 'm' represents 'maritime'. Therefore, a 'c' signifies an air mass that forms over a large land area. However, the full classification uses two letters, with the first letter indicating the moisture characteristics (continental or maritime) and the second letter indicating the thermal characteristics (polar, tropical, etc.). For instance, cP stands for Continental Polar, which is a cold, dry air mass that forms over land in higher latitudes.
The air mass classification code "c" indicates a maritime polar air mass. Air masses are large bodies of air that have similar temperature and humidity characteristics. The classification codes are based on the region from which the air mass originates and its temperature and moisture characteristics.