Which of the following commissions functions independently and is accountable to the Chief Executive?

The Commission Against Corruption (CACC) is the correct answer as it is established specifically to combat corruption and maintain integrity within the public sector. It operates independently to ensure that it can carry out its mandates without undue influence from other branches of the government. However, it is ultimately accountable to the Chief Executive, who oversees its functioning and has the authority over its operational framework.

In the context of the other options, the Commission of Audit, while it conducts independent audits, reports to the Legislative Council. The Legislative Council itself is a legislative body and does not operate under the Chief Executive's direct oversight in the same manner. The Executive Council, comprised of appointed advisors to the Chief Executive, is directly accountable to the Chief Executive and does not function independently like the CACC. Thus, the CACC stands out as the body that balances independence in its operations with accountability to the Chief Executive, making it the best choice in this scenario.