$(6$ pts$)$ A truss structure shown below is pin supported at joint $L$ and roller supported at joint $l.$ The reactions of these supports due to the applied forces at joints $C$ and $G$ have been calculated and presented in the figure below.

a$.$ Identify all zero$-$force members on the truss by writing down the members' label.

b$.$ Using the Method of Sections $($M$.$O$.$S$.),$ calculate the member forces EF$,$ JF$,$ and J

c$.$ Using the Method of Joints $($M$.$O$.$J$.),$ calculate the member forces $DK,LB,KB$ and $BJ.$