Need help solving this one specifically using finite element modeling with matrices.

For the shaft sown below, use finite element modeling to determine:

a$)$ the angles of twist at points $D$ and $B$

b$)$ The reactions at points A and $C$

Ignore the reduced section between $D$ and $B$ and take the same diameter of $1\mathrm{.}5$ in

for section DB$.$ Take G $=100{10}^3$ksi