Which of the following is post-chemotherapy based staging system in Wilms' tumor?

a. National Wilms' tumor staging system (NWTS)(Ref: Nelson's 20/e p 2464-2466, Ghai 8/e 617-618)The two major groups which have tremendous contributions in the management of Wilms' tumor are National Wilms' Tumor Study (NWTS) and the Societe Internationale D'oncologie Pediatrique (SIOP).In 2001, NWTS merged with several other pediatric oncology cooperative groups to create the Children's Oncology Group (COG). However, the NWTS is still active in name today completing follow-up of the late effects of treatment for patients previously enrolled in its trials.