After the first day of fighting at Gettysburg, the arrival of reinforcements allowed
✖ the Union to avoid more casualties.
✔ the Union to hold the line and win.
✖ the Confederacy to break the lines.
✖ the Confederacy time to regroup.
In conclusion, the answer is B.
(I am doing this for the people that come across this question and didn't know the answer.)
{hope this helped}
btw this is a question in the unit test review for grade 7 in the semester a for unit 4.