Which setting is NOT allowed?

Note the following parameter settings: Which setting is NOT allowed?

A.
ALTER SYSTEM SET DB_CACHE_SIZE=50M;

B.
ALTER SYSTEM SET DB_8K_CACHE_SIZE=10M;

C.
ALTER SYSTEM SET DB_4K_CACHE_SIZE=10M;

D.
ALTER SYSTEM SET DB_16K_CACHE_SIZE=10M;