Which file type can be used with the import function in the reference set editor window?

An administrator needs to import a list of HR staff logins into a reference set.

Which file type can be used with the import function in the reference set editor window?

A. xml

B. csv

C. xls
D. json

Reference: https://www.ibm.com/support/knowledgecenter/en/SS42VS_7.3.2/com.ibm.qradar.doc/c_qradar_adm_refdata_ui.html