PLS HELP

What helped McClellan drive Lee out of Maryland?

A. A Union officer found a paper showing Lee's battle plan.

B. Lee was wounded in the battle.

C. Lincoln sent 37,000 troops from Washington, D. C. to Maryland.

D. European countries sent reinforcements.

B

Explanation:

But draw it he would. Two days later, Lee was appointed commander of Virginia’s forces with the rank of major general. He spent the next few months raising troops in Virginia, and in July he was sent to western Virginia to advise Confederate commanders struggling to maintain control over the mountainous region. Lee did little to build his reputation there as the Confederates experienced a series of setbacks, and he returned to Richmond when the Union gained control of the area. The next year, Lee assumed command of the Army of Northern Virginia after General Joseph Johnston was wounded in battle. Lee quickly turned the tables on Union General George B. McClellan, as he would several other commanders of the Army of the Potomac. His brilliance as a battlefield tactician earned him a place among the great military leaders of all time.

the correct answer is:

b) a rich merchant.