Given is a Decision Tree Diagram. The Payoffs $1-14$ are given in the table below. Answer questions a$,$ b$,$ and c

Payoff $/$ $

$1/5$

$2/-2$

$3/7$

$4/3$

$5/3$

$6/3$

$7/2$

$8/-3$

$9/4$

$10/5$

$11/3$

$12/-3$

$13/5$

$14/4$

a$)$ The value at node $4$ is $?$

b$)$ The value at node $8$ is $?($in $1$ decimal place$)$

c$)$ The best course of action or decision is to select alternative $?$