Consider the University schema in the powerpoint slides $($image attached is complete. Details in oarts abc should be implemented in query for example dept$\_$name$="$CS$"),$ write the following query in SQL in terms of SELECT, FROM, WHERE, AND etc.

a$.$ Find the ID and name of all courses from the CS department that have more than $3$

credits.

b$.$ Find the ID and name of all students who took a course titled $$Operation Systems$$ in

Spring $2023.$

c$.$ Find the ID and name of all students who does NOT take any courses from the CS

department.

d$.$ Find all departments that have at least $3$ courses offered in the $$Memorial$$ building, and

for each of such department, list the number of courses that is offered in each building