Which database type should be used with highly structured data and provides support for ACID transactions?

Time series databases are specialized for handling data points indexed by time, not general-purpose highly structured data with strong ACID transactional needs.

Document databases are schema-less or have flexible schemas, which contrasts with the requirement for 'highly structured data', and their ACID support is often limited to single documents or eventually consistent.

Graph databases are optimized for data with complex relationships, not primarily for general-purpose highly structured tabular data with strict ACID transaction requirements.

Relational databases are fundamentally designed to manage highly structured data using predefined schemas, tables, and relationships, and they are well-known for providing robust support for ACID (Atomicity, Consistency, Isolation, Durability) transactions, ensuring data integrity.