GATE CS 2024 Set 1 Q10 — ER-model

To find the correct ER diagram, we can break down the specification $\mathrm{S}$ into its constituent entity sets and binary relationships:

1. "Instructors teach courses": A binary relationship (e.g., teaches) between the entity sets Instructor and Course.
2. "Students register for courses": A binary relationship (e.g., registers) between the entity sets Student and Course.
3. "Courses are allocated classrooms": A binary relationship (e.g., allocated) between the entity sets Course and Classroom.
4. "Instructors guide students": A binary relationship (e.g., guides) between the entity sets Instructor and Student.

This gives us four entity sets: Instructor, Course, Student, and Classroom, with the following connections:

• Instructor $\leftrightarrow$ teaches $\leftrightarrow$ Course
• Student $\leftrightarrow$ registers $\leftrightarrow$ Course
• Course $\leftrightarrow$ allocated $\leftrightarrow$ Classroom
• Instructor $\leftrightarrow$ guides $\leftrightarrow$ Student

Only diagram (iv) correctly represents all four of these binary relationships between the correct entity sets as specified.

Therefore, the correct option is D (corresponding to diagram (iv)).