The most common adverb suffix is the suffix.
1. -long
2. -way
3. -ward
4. -ly

The correct answer is 4. -ly

Explanation:

To begin with, a suffix is one letter, multiple letters or a syllable added at the end of words that affect the meaning of it and also in some cases changes the category of the world. On the other hand, an adverb is a word that describes or modifies verbs by showing place, time, way, frequency, etc. In the English language, these type of words are mainly formed by adding the suffix "-ly" to adjectives as in slowly, carefully, rarely, absolutely, etc and because of this the suffix "-ly" is the one that identifies adverbs and it is the most common. Although other words such as here, never and down are also adverbs.

moon-letters were a method of writing invented by the dwarves. moon-letters were ordinary runes, but written in such a way that they could only be read when the light of the moon shone behind the writing. some moon-letters could be read by any moonlight, but it was possible to make the writing even more secret. more sophisticated moon-letters could only be read by the light of the same shape of moon, or at the same time of year, as when they were written. hope this !

the answer should be d) he was one of those young thousands who greeted the war with a certain amount of relief, welcoming the liberation from webs of tangled emotion" since it is the best option because it shows his desire to free himself. 

hope this answer you! have a great day.