Some Countries Seek the Advantages of Agglomeration

Some countries seek the advantages of agglomeration. What are advantages of agglomeration?

A) Per unit costs may be lower when production occurs on a larger scale.
B) When a country gains global market share in an industry, its dominance provides higher profits to producers.
C) Agglomeration allows workers to produce remotely from any location, providing more even job growth across a country.
D) Some industries are more productive when workers in the industry regularly interact with other workers in the same industry or closely related industries.