C. He curses both families involved in the feud
<span>According to the rules the best anser from given above is D) because the base word ends in a vowel followed by the letter y. We don't use changing to "i" with the words that end in ay, ey, oy, uy. But we have an exeption like day => daily but NOT dayly.</span>
The correct transition word to link the two sentences would be conversely.