Which statement is most appropriate?

a. Variety creates a richness and degree of flexibility in the type of audit work that is undertaken. In many cases, an audit department will contain different types of auditors who collectively discharge the audit function. Internal auditing is about evaluating management and this should be a central theme in most audit work.

b. Variety creates a richness and degree of flexibility in the type of audit work that is undertaken. In many cases, an audit department will contain different types of auditors who collectively discharge the audit function. Internal auditing is about evaluating risk management and internal controls and this should be a central theme in most audit work.

c. Variety creates a richness and degree of flexibility in the type of audit work that is undertaken. In many cases, an audit department will contain different types of auditors who individually discharge the audit function. Internal auditing is about evaluating risk management and external controls and this should be a central theme in most audit work.

d. Variety creates a richness and degree of flexibility in the type of audit work that is undertaken. In many cases, an audit department will contain different types of auditors who collectively discharge the audit function. Internal auditing is about evaluating risk management and internal controls, but this need not be a central theme in most audit work.