T$1$ : $250$ kNm

T$2$ : $350$ kNm

T$3$ : $450$ kNm

AI : $80$ mm

IB : $80$ mm

BII : $90$ mm

IIC : $90$ mm

CIII : $100$ mm

IIID : $100$ mm

R$1$ : $30$ mm

R$2$ : $20$ nm

R$3$ : $10$ mm

G : $75000$ MPa

find reaction at A and D$,$ calculate the shear stress because of torsion of each segments and find twist angle of each segments