You want to add the suffix ed to the following words. Which word would require you to change the y to an i?

Betray

Destroy

Hurry

Obey

Betray, Destroy, and Obey do not need to be changed to add the suffix - ed, because the "y" at the end of each word is preceded by a vowel (so they would be spelled "betrayed," "destroyed," and "obeyed").

But hurry is different; it has to be spelled "hurried" because the "y" at the end of "hurry" is preceded by a consonant.