​Which of the Following Is True of Sustainability Assurance

​Which of the following is true of sustainability assurance?

A) ​It is the external verification that an independent party provides concerning the content of a corporate sustainability report.
B) ​Traditionally, most organizations have found it much easier to estimate the benefits of corporate sustainability reporting (CSR) assurance than the costs.
C) ​The cost of corporate sustainability reporting (CSR) assurance is always negligible.
D) ​The lack of a generally accepted set of reporting standards for preparing corporate sustainability reports leads to lower assurance costs.