Answer:
Option D. The map illustrates how Union forces overwhelmed confederate defenses and continued their march.
Step-by-step explanation:
Between March 29th and March 31st of 1863, General Grant followed by the Union army initiated what is known as "Grant's march" which was a campaign that went from Tennessee down the Mississippi river and into Vicksburg. The campaign consisted of several battles and was a significant victory for the Union forces, as they dominated one of the last areas controlled by the Confederate forces.
As the map shows, the Union forces overwhelmed confederate defenses as they continued their march towards Vicksburg, defeating the Confederate in all the occasions they met through the Mississippi river area.