Why did the Confederates create the submarine? A. to distract Union ships while Confederate ships snuck by
B. to go under the naval blockade created by Southern ships
C. to break through the naval blockades created by Union ships
D. to inspire Europeans to denounce the Union’s naval blockade

The South's sub actually scored the first kill by a submarine in history. However, the submarine did not survive.

Explanation:

A     The Vicksburg campaign was a series of maneuvers and battles in the Western Theater of the American Civil War directed against Vicksburg, Mississippi, a fortress city that dominated the last Confederate-controlled section of the Mississippi River. The Union Army of the Tennessee under Maj. Gen. Ulysses S. Grant gained control of the river by capturing this stronghold and defeating Lt. Gen. John C. Pemberton's forces stationed there.

B       The blockade was proclaimed by President Abraham Lincoln in April 1861, and required the monitoring of 3,500 miles (5,600 km) of Atlantic and Gulf coastline, including 12 major ports, notably New Orleans and Mobile. Those blockade runners fast enough to evade the Union Navy could only carry a small fraction of the supplies needed. They were operated largely by foreign citizens, making use of neutral ports such as Havana, Nassau and Bermuda. The Union commissioned around 500 ships, which destroyed or captured about 1,500 blockade runners over the course of the war.

C       The Confederacy experimented with using submarine vessels to destroy Union blockade ships for months in 1863 and 1864.

D      During the Civil War, Union forces established a blockade of Confederate ports designed to prevent the export of cotton and the smuggling of war materiel into the Confederacy. The blockade, although somewhat porous, was an important economic policy that successfully prevented Confederate access to weapons that the industrialized North could produce for itself. The U.S. Government successfully convinced foreign governments to view the blockade as a legitimate tool of war. It was less successful at preventing the smuggling of cotton, weapons, and other materiel from Confederate ports to transfer points in Mexico, the Bahamas, and Cuba, as this trade remained profitable for foreign merchants in those regions and elsewhere.

formulating the initial idea for the policy

answer is c.