What did union general george meade do that enabled his forces to win at gettysburg on the third day of battle?

The actual fact is the Union General Meade did nothing except hold his own ground without trying to attack the Confederate army. This might look simple but it was a great and effective strategy. On the 3rd and the final day of the famous battle of Gettysburg the Confederate army attacked with a strong army of 12,500 men. This famous charge on the Cemetery Ridge is also known as the Pickett’s Charge. This charge was well repulsed by the artillery and the gunmen of the Union army controlled by General Meade. This charge led to huge losses for the Confederate army and they never again turned back for fighting.  

Cis the on

Ithink it would be choices a and b. hope this !