The given root word above is the word "envy" and the rule that applies to this word is option C. Group III. The suffix -able always follows i. With the word envy, the last letter "y" should be changed to "i" then add a vowel suffix. In Group III, as stated, we change the "y" to "i" then add -able, so the word becomes "enviable" making it an adjective. Hope this helps!
