Answer:
Probably the fourth option
Explanation:
The fourth option because the way the author is ending the paragraph seems like they are saying that the industrial revolution will have unknown consequences. (Said the seventh grader lol)
A comma indicates a pause between the ending of an introductory word, phrase, or clause, and the beginning of the main part of the sentence.
# A comma is used before any coordinating conjunction (and, but, for, or, nor, so, yet) that links two independent clauses. ....
#It is also used after a dependent clause that starts a sentence. ...
#Commas also used to offset appositives from the rest of the sentence. ...
#They are used to separate items in a series. (this is the most commonly used)
The Ageing of process :-)................................
