lets start from scratch..
first deal with the multivalued attributes E and F
we need a separate table for them with either A or B ...means ABCD and AEF or BEF
now we are in 1NF with 2 tables
move towards 2NF...now from hereon we need FDs to further divide the tables..but since they are not mentioned we cant do anything and these 2 tables are by default in 2NF and BCNF too,,,
what if FDs were given?
then we need to check..but then also ABCD is in 2NF since A and B are 2 single attributes...there cant be any partial dependency...for 3NF there shouldnt be any FD like C->D or D->C else decompose...
for BCNF u shouldnt have any dependency like C->A or C->B or D->A or D->B...rest fine
so for ur question since no FDs were given finally u'll have 2 tables for 1NF,2NF,3NF,BCNF....else even if FDs were given it was in 2NF atleast rest u need to check for..
for 4NF...just split E and F also in 2 separate tables...