Answer:
RANT.
Explanation:
As per the question, the word 'RANT' best fills the given sentence as it best comprehends and accomplishes the meaning as per the context of the statement. The word 'rant' implies 'criticism by shouting uncontrollably' which best brings about the essence of the statement. Thus, the sentence would signify that:
'He went into a long rant(criticism in an impassioned manner) about the outcome of the last election after it was mentioned on the news.'
Thus, this reflects that the person got involved in criticism that reached up to the extent of shouting and yelling. Therefore, 'rant' is the correct answer.