The battle of antietam in 1862 put an end to

yup! you are correct it is b.

the section of the chart that represents a point at which a bill needs approval from a majority of people in both chambers to advance is j, as this is the only section before the bill becomes law which has both rows (symbolizing the chambers) converging into one, meaning that the two parts of the congress have to approve of it before it can march on with the process.