The correct answer is A based on Snowflake's official best practices for data ingestion. According to Snowflake documentation and the community discussion, files in the 100-250 MB range offer the best cost-to-performance ratio for Snowpipe. This size range minimizes the per-file overhead charge relative to the total data loaded, making the overhead cost immaterial. Option B (100-250 GB) is too large and not practical for typical Snowpipe operations. Option C (10-100 MB) is the minimum recommended size but not optimal. Option D (1-2 GB) is larger than the recommended range and may not provide the same cost efficiency.