Which revision of sentence 8 is punctuated correctly?
A.
"In February of 1850 President Taylor held a heated conference with leaders, who threatened to secede from the Union."
B.
"In February of 1850, President Taylor held a heated conference with leaders, who threatened to secede from the Union."
C.
"In February of 1850, President Taylor held a heated conference with leaders who threatened to secede from the Union."
D.
"In February of 1850 President Taylor held a heated conference, with leaders who threatened to secede from the Union."
