Answer:
The necessary ingredients to prevent the filling from burning are:
C) Egg, chicken broth.
Step-by-step explanation:
The egg in any filling creates a layer on the dough when adding heat to the dough the egg is heated first causing the dough to become crispy and preventing the filling from burning. Something like a protective layer.
And the chicken broth causes the filling to become moist, this in order to prevent heat from burning the filling before the dough is at its point, since the heat is kept inside the dough and can burn the filling first.