Problem $1(25$ pts$)$ The statically determinate steel frame shown below ts fixed at $A,$ and $B,C,$ and $D$ are pins. Determine $($i$)$ suppart reactions at A and $D,$ and then $($it$)$ plot the shear force and bending moment diagrams of member BC$.($Hint: toke advantage of the equations of conditions associated with the pins at $B$ and $C).$