Step 1: Understanding archival analysis.
Archival analysis involves the systematic study of existing records and documents rather than direct interaction with participants.
Step 2: Identifying the correct method.
Materials such as newspapers, magazines, letters, and diaries provide historical and cultural data that researchers analyze to understand social patterns.
Step 3: Eliminating incorrect options.
Surveying and observing involve direct data collection, while cross-cultural comparison relies on observational methods rather than archival records.
Step 4: Conclusion.
Thus, archival analysis describes culture through the examination of existing documents.
Final Answer: (A)