Sentence Correction (SC) | Re: Garibaldi captured Rome in 1870, in the final step in Italian Reunific

Garibaldi captured Rome in 1870, in the final step in Italian Reunification, and as a consequence, the Vatican had ceased holding an army and had become a purely religious institution.

Before jumping to answer the question , I had doubt regarding the placement of commas before and after "and as a consequence" . If remove the modifier the sentence is basically "Garibaldi captured Rome in 1870 and as a consequence, " what is the use of the comma after consequence?

I chose
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