We consider the following relation Stock. The primary key of Stock is prodid, depid.

prodid	depid	prodname	quantity
p1	d1	vcr	10
p1	d2	vcr	20
p2	d3	tv	30

(a) Write the following query in relational algebra. What are the prodnames? (b)Write the following query in relational algebra. What are the ids of the depts that are stocked with a quantity > 20? (c) Write the following query in SQL. What is the average of the quantity of EACH depot? (quantity > 0) (d) Write the following query in SQL. What is the sum of the quantities of EACH depot? (quantity> 0) (e) The primary key of Stock is prodid, depid What trivial functional dependencies can you deduce from this fact?(f) Is there redundancy in the Stock table? Explain.