Step 1: Picture a chain of dependency.
Suppose a table has a primary key that determines a non key attribute B, and B in turn determines another non key attribute C. This chain, key determines B, B determines C, means C actually depends on the key only indirectly, through B, this indirect chain is called a transitive dependency.
Step 2: Recall what each normal form fixes.
First Normal Form only ensures atomic values in each column. Second Normal Form removes partial dependency, where a non key attribute depends on only part of a composite key. Third Normal Form goes a step further and requires that every non key attribute depend directly on the whole key and nothing but the key, which is precisely what eliminates the chain described above.
Step 3: Note BCNF as a stricter cousin.
BCNF is a stronger version of 3NF that handles some extra edge cases involving overlapping candidate keys, but the specific job of breaking transitive dependencies is already completed once a table reaches 3NF.
Step 4: Conclude.
The normal form that removes transitive dependencies is
\[ \boxed{\text{3NF}} \]