Final answer:
If the control environment is assessed to be weak, auditors may respond by altering the audit plan to include more audit procedures and expanding the scope of the audit to include more of the client's locations.
Step-by-step explanation:
If the control environment is assessed to be weak, option 1) auditors may respond by altering the audit plan to include more audit procedures and expanding the scope of the audit to include more of the client's locations is the correct response. When the control environment is weak, it means that the internal controls of the organization are not effective in preventing or detecting errors or fraud. In such cases, auditors need to increase the level of testing and scrutiny to obtain sufficient assurance about the reliability of the financial statements.