Answer:
The correct answer is b) Because the Union had control of the Mississippi and would not let them pass.
Step-by-step explanation:
The United States civil war began in 1861, fighting the northern states against the southern ones. Because the southern states were against new laws that abolished slavery, racial differences and fueled the development of industries. The southern cities that made up the Confederate States of America were opposed to freeing slaves because they would have no one to do the agricultural work that fueled their economy.
During the civil war, many battles were carried out with a large number of soldier casualties, Texas played an important role supplying food and soldiers to fight the union of the northern states, a situation that ceased when the northern union took control of the Mississippi River, preventing Texan soldiers from crossing the river and continuing to support the Confederate soldiers from the south.
I hope this information can help you.