Answer:
D
Step-by-step explanation:
The opposite angles of the inscribed quadrilateral are supplementary
∠A + ∠C = 180 and ∠B + ∠D = 180
∠B + ∠D = 93 + x + 30 = x + 123, hence
x + 123 = 180 ( subtract 123 from both sides )
x = 57 → D
