Which sentence correctly uses a comma to separate the introductory phrase?

Which sentence correctly uses a comma to separate the introductory phrase?
a. Commerce is represented by, the female statue crowned with a wreath of olive leaves.
b. The female statue, crowned with a wreath of olive leaves, represents commerce.
c. Crowned with a wreath of olive leaves, this female statue represents commerce.
d. The wreath of olive leaves crowning the female statue, represents commerce.