$($a$)$ In DAG $1,$ is $E_{|}{?}_D?$ How about in DAG $2?$ Please explain.

$($b$)$ In DAG $2,$ are E and D independent conditional on each of the following sets of variables?

Please explain.

i$.\{T\}$

ii$.\{P\}$

iii. $\{R\}$

iv$.\{T,R\}$

v$.\{P,R\}$

$($c$)$ List all pairs of variables in DAG $1$ that are independent conditional on the set of variables

$\{R,V\}.$