Use the following relational schema for this homework: Sailors$($sid: integer, sname: string, rating: integer, age: real$)$ Boats$($bid: integer, bname: string, color: string$)$ Reserves$($sid: integer, bid: integer, day: date$)$ Reserves $$: $100,000$ tuples stored in $1,000$ pages. There are $100$ boats. Each boat is equally poplar $($i$.$e$.,$ each has the same number of reservations$).$ Sailors $($S$)$: Stored in $500$ pages. There are $10$ distinct rating levels $(1$ to $10),$ each with the same number of sailors. $1.$ The sid column takes up $20\%$ of the data size of the Reserves relation. The sid and sname columns take up $70\%$ of the data size of the Sailor relation. a$.$ If you are given $3$ memory pages, describe an efficient execution plan for the execution tree in the right. b$.$ Estimate the processing time $($I$/$O cost$)$ of your computation stratgegy. You do not have to include the cost of writing the query result in your analysis. $2.$ If you have $4$ memory pages, explain a better computation strategy to take advantage of the one extra memory page for the execution tree in the right. Estimate the processing time $($I$/$O cost$).$ You do not have to include the cost of writing the query result in your analysis.