A. Believe
In any sentence, the best replacement for a word is its synonym (a word that means the same thing). Since believe is a synonym for accept, the sentence still makes sense. The other words listed are all antonyms (words that mean the opposite) and would therefore change the meaning of the sentence.
“Jeremy could not accept that his team lost the tournament” and “Jeremy could not believe that his team lost the tournament” have the same meaning, that Jeremy was surprised his team didn’t win.
