to place this in 2NF we see that E and F is depended on D.
and B and C is functionally depended on A.
So you would have tables:
which leaves in in 2NF, because none of D, E or F is depended on A.
To place this now in 3NF we have to eliminate transitive dependencies. This is A->B->C thus C is transitively dependent on A since A NOT -> C.
When eliminating these you just split it up further and have resulting database in 3NF: