Explanation
To arrange the words in alphabetical order as they would appear in a dictionary, we compare them letter by letter from left to right.
All four words start with the letters Jo.
Looking at the third letter of each word, Jockey, Jocular, and Jocund have c, while Joke has k. Since c comes before k in the alphabet, Jockey, Jocular, and Jocund will appear before Joke. This makes Joke the last word in the sequence.
Now we compare the remaining three words which all start with Joc.
The fourth letter of Jockey is k, while the fourth letter of Jocular and Jocund is u. Since k comes before u, Jockey is the first word in the sequence.
Finally, we compare Jocular and Jocund. Both share the first four letters Jocu. Looking at the fifth letter, Jocular has l and Jocund has n. Since l comes before n, Jocular comes before Jocund.
This gives the final alphabetical sequence as Jockey, Jocular, Jocund, and Joke, which corresponds to the order ii, iii, iv, i.