$[25$pts$]($Exercise $14\mathrm{.}2)$ Consider a relation $R(A,B,C,D,E)$ containing $5,000,000$ records, where each data

page of the relation holds $10$ records. $R$ is organized as a sorted file with secondary indexes. Assume that $R.A$

is a candidate key for $R,$ with values lying in the range $0$ to $4,999,999,$ and that $R$ is stored in $R.$A order. For

each of the following five relational algebra queries, state which of the following six approaches $($or combination

thereof$)$ is most likely to be the cheapest:

Access the sorted file for $R$ directly.

Use a clustered $B^{+}-$tree index on attribute $R.A.$

Use a linear hashed index on attribute R$.$A$.$

Use a clustered $B^{+}-$tree index on attributes $(R.A,R.B).$

Use a linear hashed index on attributes $(R.A,R.B).$

Use an unclustered $B^{+}-$tree index on attribute $R.B.$

$($a

$($b

$($c$){}_A>50,{000}^{{?}^{?}}B=50,000(R)$

$($d$){}_{A}50,{000}^{{?}^{?}}B=50,000(R)$

$($e