Using the provided database answer the questions using relational algebra

• classroom
  • building string
  • room_number number
  • capacity number
• department
  • dept_name string
  • building string
  • budget number
• course
  • course_id string
  • title string
  • dept_name string
  • credits number
• instructor
  • ID number
  • name string
  • dept_name string
  • salary number
• section
  • course_id string
  • sec_id number
  • semester string
  • year number
  • building string
  • room_number number
  • time_slot_id string
• teaches
  • ID number
  • course_id string
  • sec_id number
  • semester string
  • year number
• student
  • ID number
  • name string
  • dept_name string
  • tot_cred number
• takes
  • ID number
  • course_id string
  • sec_id number
  • semester string
  • year number
  • grade string
• advisor
  • s_id number
  • i_id number
• time_slot
  • time_slot_id string
  • day string
  • start_hr number
  • start_min number
  • end_hr number
  • end_min number
• prereq
  • course_id string
  • prereq_id string

A- Instructor(s) who taught course(s) offered by different department they are associated with. Retrieve IDs and names of these instructors only.

B- Course(s) with prereqisite(s) from other departments. We are interested in course id(s), title(s) and dept name(s) of a course with its prerequisites course_id(s), title(s) and dept_name(s).

C- Course section(s) what student(s) enrolled in but no one taught. We are interested in course_id(s), sec_id(s), semester(s), year(s) here.

D- Student(s) taught by their advisor. We are interested in ID(s) and name(s) of this\those student(s).