When a Question Arises Regarding the Going-Concern Basis, Additional Procedures

When a question arises regarding the going-concern basis, additional procedures may be necessary.Which of the following procedures is an example of a valid additional procedure?

A) Evaluate management's plans for future actions in relation to its going concern assessment.
B) Consider whether any additional facts or information have become available since the date on which management made its assessment.
C) Where the entity has prepared a cash flow forecast, and analysis of the forecast is a significant factor in considering the future outcome of events or conditions in the evaluation of management's plans for future actions, determine whether there is adequate support for the assumptions underlying the forecast.
D) All of the above.