Yesh opens a lemonade stand for $2$ hours. He spends $$10$ for ingredients and sells $$60$ worth of lemonade. In the same $2$ hours, he could have mowed his neighbor's lawn for $$40.$ Yesh earns an accounting profit of

$q,$ and an economic profit of $q,$

A$.$ $$10$;$$50$

B$.$ $$50$;$$10$

C$.$ $$50$;$$90$

D$.$ $$90$;$$50$