Read and analyse the following case study to provide answers to the given questions.

Chelsea is a lead consultant in a top-level consulting firm that provides consultant services including how to set up secure corporate networks, designing database management systems, and implementing security hardening strategies. She has provided award winning solutions to several corporate customers in Australia. In a recent project, Chelsea worked on an enterprise level operations and database management solution for a medium scale retail company. Chelsea has directly communicated with the Chief Technology Officer (CTO) and the IT Manager to understand the existing systems and provide progress updates of the system design. Chelsea determined that the stored data is extremely sensitive which requires extra protection. Sensitive information such as employee salaries, annual performance evaluations, customer information including credit card details are stored in the database. She also uncovered several security vulnerabilities in the existing systems. Drawing on both findings, she proposed an advanced IT security solution, which was also expensive due to several new features. However, citing cost, the client chose a less secure solution. This low level of security means employees and external stakeholders alike may breach security protocols to gain access to sensitive data. It also increases the risk of external threats from online hackers. Chelsea strongly advised that the system should have the highest level of security. She has explained the risks of having low security, but the CTO and IT Manager have been vocal that the selected solution is secure enough and will not lead to any breaches, hacks or leaks

Question:

Suppose you are a member of Chelsea's IT security team. She has asked you to perform a k-anonymity evaluation for the below dataset. The quasi-identifiers are {Sex, Age, Postcode} and the sensitive attribute is Income. In the context of k-anonymity: Is this data 1-anonymous? Is it 2-anonymous? Is it 3-anonymous? Is it 4- anonymous? Is it 5-anonymous? Is it 6-anonymous? Explain your answer.