This is the answer. I don’t understand the last part you post
Hello!

The subject of this sentence is "Yo" (I), so we must use the first-person singular conjugation.
Thus, the correct conjugation ends with an "o", or "Pruebo". Choice A is the correct answer.
<span>500 millas en 10 <span>horas
that is how you say "500 miles in 10 hours" in Spanish
Hope this helped
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B is the future form for yo.