QUESTION 4 (20 MARKS) The "Big Four" global professional services organisations, Deloitte, EY, KPMG, and PWC, collectively audit 97% of US public companies and all largest corporations, and they are the market leaders in auditing large enterprises. In addition to audit, they offer a wide range of profitable consulting services. They dominate the audit of multinational corporations due to their extensive global reach and proficiency in intricate cross-border corporate structures. However, each of the Big Four has been charged with conducting shoddy audits and failing to uncover activities tied to wrongdoing, such as money-laundering. The fact that these businesses increasingly have conflicts of interest by pursuing lucrative consulting contracts with the same clients is a big cause for concern because it has compromised their auditors. Required: a. Discuss FOUR (4) criterias that should be considered when using the work of other auditors of group accounts. (10 marks) b. Highlighting the impact of sample risk can result in the auditor drawing the incorrect conclusion. Support your answer with ONE (1) example. (10 marks)