Consider the following relational schema:
instructor(ID, name, dept_name, salary)
teaches(ID, course_id, sec_id, semester, year)
course(course_id, title, dept_name, credits)
What is the relational algebraic expression to find the names of all instructors in the Comp.Sci. department together with the course titles of all the courses that the instructors teach?
1
\(∏_{name,title}(∏_{dept \_name="Comp.Sci.”}(instructor⋈teaches⋈course) \)
2
\(∏_{name}(σ_{dept \_name, title= "Comp.Sci.”}(instructor⋈teaches⋈course) \)
3
\(∏_{name,title}(σ_{dept \_name="Comp.Sci.”}(instructor⋈teaches⋈course) \)
4
\(σ_{name,title}(∏_{dept \_name="Comp.Sci.”}(instructor⋈teaches⋈course) \)
5
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