Why did general general charles cornwallis retreat from the carolinas and march north into virginia?

Cornwallis had decided he could not win the Carolinas after suffering losses in  two major battles. As a result, much of his Army was sick or wounded. Everywhere in the area the Americans had gained strength. Also, the Americans had successfully defeated his Loyalist supporters in the area and most of them had dispersed making his fortunes unfavorable

length of the cultivating season was not a problem of new england agriculture

your answer will most likely be a.