According to IIA guidance, which of the following must internal auditors consider to conform with the requirements for due professional care during a consulting engagement?

1. The cost of the engagement, as it pertains to audit time and expenses in relation to the potential benefits.

2. The needs and expectation of clients, including the nature, timing, and communication of engagement results.

3. The application of technology-based audit and other data analysis techniques, where appropriate.

4. The relative complexity and extent of work needed to achieve the engagement's objectives.