What is the MOST cost-effective solution?

Explanations:

Amazon S3 Glacier is designed for long-term archival storage and has retrieval delays, making it unsuitable for nightly log processing that requires timely access.

Amazon S3 Standard provides low-latency access and is ideal for frequently accessed data, making it the best choice for nightly log processing that needs immediate availability.

Amazon S3 Intelligent-Tiering is useful for optimizing costs over time by moving data between access tiers, but it incurs additional costs for monitoring and does not specifically cater to short-term, frequent access needs.

Amazon S3 One Zone-IA is designed for infrequent access data, but since the logs are only retained for 24 hours and likely accessed frequently during that time, S3 Standard is more appropriate for performance and cost-effectiveness.