Choice "A" is correct. ERM provides a framework in which to manage risk within an organization's risk appetite to provide reasonable assurance regarding the achievement of entity objectives. The assertion that ERM can provide absolute assurance with respect to objective categories is not true but, if it were, it would represent a strength and not a weakness.
Choice "b" is incorrect. ERM provides a framework in which to manage risk within an organization's risk appetite to provide reasonable assurance regarding the achievement of entity objectives. The uncertainty of future events or risks addressed by ERM potentially limits the effectiveness of the framework.
Choice "c" is incorrect. ERM provides a framework in which to manage risk within an organization's risk appetite to provide reasonable assurance regarding the achievement of entity objectives. The complexity of ERM can limit its effectiveness. ERM components are applied to each objective from the entity through the subsidiary level.
Choice "d" is incorrect. ERM provides a framework in which to manage risk within an organization's risk appetite to provide reasonable assurance regarding the achievement of entity objectives. Like any control mechanism, the effectiveness of the framework is limited by the capabilities of the individuals responsible for implementation.