Regarding IFRS 15, Revenue Recognition Revenue from Contracts with Customers, which of the following statements is true for IFRS reporting companies:

A. For all companies, the effective date is for reporting periods beginning on or after January1, 2018.

B. Early adoption is permitted only for public companies.

C. For nonpublic companies, the effective date is for reporting periods beginning after December 15, 2017.

D. For nonpublic companies, the earliest permitted adoption date is for reporting periods beginning on or after January 1, 2018.