A company needs to export its database once per day to Amazon S3 for other teams to access. Exported object sizes range from 2 GB to 5 GB. The S3 access pattern is variable and changes rapidly. The data must be immediately available and remain accessible for up to 3 months. The company wants the most cost-effective solution without increasing retrieval time. Which S3 storage class should the company use?

S3 Intelligent-Tiering is the most cost-effective solution because it automatically moves objects between access tiers based on changing access patterns, optimizing costs without performance impact. Since the access pattern is variable and changes rapidly, Intelligent-Tiering ensures data is in the most appropriate tier (frequent or infrequent access) without manual intervention or retrieval charges. The data remains immediately available. S3 Glacier Instant Retrieval is incorrect because while it offers low cost and immediate retrieval, it's designed for data accessed once a quarter, not variable access patterns. S3 Standard is incorrect because it's optimized for frequently accessed data, and while it meets availability requirements, it would be more expensive than Intelligent-Tiering for variable access. S3 Standard-Infrequent Access (S3 Standard-IA) is incorrect because it's for infrequently accessed data, and the variable access pattern would incur higher retrieval costs.