Question: Find the name of the department that offers the largest number of credits of all classes.
SQL: SELECT T3.dept_name FROM course AS T1 JOIN CLASS AS T2 ON T1.crs_code  =  T2.crs_code JOIN department AS T3 ON T1.dept_code  =  T3.dept_code GROUP BY T1.dept_code ORDER BY sum(T1.crs_credit) DESC LIMIT 1