Answer:
D. all of the above.
(I was thinking both C and B since they apply to a stem change. I wasn't sure about A, but I decided on D because it sounds reasonable)
Explanation:
Examples of stem changing verbs are:
Querer= quiero (e --> ie; keeps the proper ending of "yo")
Pedir= pides (e --> i; keeps the proper ending if "tu")
Sugerir= sugieren (e --> ie; keeps the proper ending of "ustedes")
Volver= vuelve (o --> ue; keeps the proper ending of "usted")
I hope this helps! :))) If something's wrong, let me know!
