Answer:
The correct option is explanation or illustration.
Step-by-step explanation:
Adverbs are commonly defined as words that describe or modify verbs, adjectives or other adverbs, explaining how, when, where, what extent and why. Particularly the word "actually" is an adverb that means in reality, in fact, as a matter of fact, in truth, in actual fact, as it happens.
Bearing the explained above, it could be said that the keyword "actually" could be used for explanation or illustration of a particular idea.