How did Grant first begin the siege on Vicksburg?

He detonated several barrels of gunpowder.

He had the navy issue an artillery assault.

He called for a "fake surrender" of his troops.

He dug trenches and tunnels underneath Vicksburg.

B - He had the navy issue an artillery assault.

Option B. He had the navy issue an artillery assault is the right answer.

Explanation:

Major General Ulysses S Grant planned the blockade of Vicksburg to restrict the food and other supplies from the ports of Mississippi to the Confederate states as it was the major port of supply to the south.

He commanded his artillery to continuously blast the Confederate troops in the city for many long hours. But Confederate troops easily retaliated and chased away the union troops. Again Grant planned his siege; Grant stated to construct huge entrenchments and many confederate troops got stuck in those large craters in Vicksburg.

By this time half of the troops were famished and susceptible to prolonged ailments which forced the Confederate forces under General John C Pemberton, to surrender. This restriction of Vicksburg was the major event which aggravated American Civil War as Mississippi came under the control of Union forces.