In the interrupting word, the actual meaning of the word rupt is "break" and the rupt word is coming from the Latin word which means burst. The rupt word is better as compared to the rood word as suffix and prefix.
The root word is one of the part of the word that are formed on the basis of the new word with the additional of suffixes and the prefix. By using the origin of the interrupting that is rupt we can make different types of word in the English vocabulary such as interrupt, disrupt and rupture.
A. break, because if you were to interrupt someone mid-conversation you would essentially be 'breaking' their speech. In erupt it seems more like burst but could also be break because the lava erupting from the volcano breaks or damages its surroundings. Just a guess.
