Respuesta :
I have finally mastered new tricks for the half-pipe: the poptart, the barrel roll, and the miller flip.
The answer is D: I have finally mastered new tricks for the half-pipe: the poptart, the barrel roll, and the miller flip.
In very basic terms, the colon always precedes an explanation or an enumeration. In this case, it precedes an enumeration, therefore, the only sentence that fills this requirement with full meaning is answer D because the tricks that have been mastered for the half-pipe are the three enumerated right after the colon.