How would you correct the following run on sentence? the student completed the exam they failed because they did not study.
A. add a semicolon between the two independent clauses where the second independent clause  begins with a capitalized letter
B. Join the two independent clauses with a coordinating conjunction followed by the comma
C. Add a semicolon   followed by a dependent clause 
D. Add a semicolon than a transition then a comma between the two independent clause