Approver Comments:
Good research! Renia likely is Rywka Mroz, as Rywka is a common nickname for Renia. Furthermore, upon searching, Renia Mroz is the only Mroz that can be found that would be the correct age for School #10B, and there are no other females with the last name Mroz in that age range. Thus, it is very likely that Renia Mroz is the person who signed the album.