Instructions: There are $16$ multiple$-$choice questions: Mark the best answer from those listed. There is only one correct answer for each problem.

Questions $1-4$:

Consider the following relations:

Emp$($eid: integer, ename: varchar, sal: integer, age: integer, did: integer$)$

Dept$($did: integer, budget: integer, floor: integer, mgr eid: integer$)$

Salaries range from $$10,000$ to $$100,000,$ ages vary from $20$ to $80,$ each department has about five employees on average, there are $10$ floors, and budgets vary from $$10,000$ to $$1$ million. You can assume uniform distributions of values.

Question $1$

$5$ pts

For the query "Print ename, age, and sal for all employees," which of the listed index choices would you choose to speed up the query if your database system does consider index$-$only plans?

Clustered hash index on