3. Using the database instance below and for each query to the right, give: a relational algebra expression

a) List the names of students whose phone number is 555- 1234.

Name

C Brown

Snoopy

b) Find the names and corresponding course numbers of all students who have a class in the Turing Aud.

Name	Course
C Brown	CS101
L Van Pelt	CS101
Snoopy	CS101

c) Find the name and phone number of students taking any of the immediate prerequisites of CS120.

Name	Course
C Brown	555-1234
L Van Pelt	555-5678
Snoopy	555-1234

SNAP tudentID Name ddress Phone 2345 Brown 12 Apple St. 55-1234 7890 . Van Pelt 34 Pear Ave 55-5678 Patt 6 Grape Blvd. 555-9999 noo 12 Apple St 55-1234 CR ourse oom S101 uring Aud E20025 Ohm Hall 100 Newton Lab CDH ourse Day our S101 M S101 S101 AM AM AM E200 10AM