Problem #$4$: Trusses $-$ method of joints $(14$ points$)$

a$)$ Find the force in member $BC.$ Specify if tension $(T)$ or compression $($C$).$ Draw any relevant free$-$body diagrams. Hint: you do not need to know the support reaction at point $C.$

b$)$ Find the force in member BD$.$ Specify if tension $(T)$ or compression $($C$).$ Draw any relevant free$-$body diagrams.

c$)$ Find the force in member $AD.$ Specify if tension $(T)$ or compression $($C$).$ Draw any relevant free$-$body diagrams.