Quality assurance (QA) primarily focuses on ensuring that the processes and standards used in the production of a product (software or otherwise) are effective, which ultimately leads to the creation of a high-quality product. Based on the options you provided, the most fitting definition of quality assurance would be:
all software requirements have been met.
While data quality, team roles, and syntax errors are important aspects of a project, QA specifically encompasses the broader goal of meeting all requirements and standards needed for quality.