Choice "B" is correct. An engagement to express an opinion on internal control will generally be more extensive in scope than the assessment of control risk made during a financial statement audit of a nonissuer. This occurs because assessing control risk is the primary purpose of an engagement to express an opinion on internal control, whereas it is an incidental result of an audit of a nonissuer.
Choice "c" is incorrect. Since examination of internal control should be integrated with the financial statement audit, it is unlikely that the auditor would duplicate procedures that were already applied.
Choice "a" is incorrect. It is unlikely that the reliability of the financial statements would be increased if an engagement to express an opinion on internal control is performed; however, the audit might be more efficient due to the integration of the two audits.
Choice "d" is incorrect. An engagement to express an opinion on internal control is more extensive in scope than the control risk assessment performed during an audit of a nonissuer.