Closed-loop function. Need help to check if my answer is correct
Yes - as mentioned by jp314, the denominator N(s) always is N(s)=(1-loop gain) and the (negative) loop gain is (-Forward*Return).

More than that, please note that for the transfer function GD(s) the "desired angle" input must be set to zero. Hence, we simply have GD(s)=B/(1+AB).