Which sentence includes a compound-word preposition?

a. there was no one at home but me.
b. the younger boys decided to play tag.
c. the lightning struck from out of the blue.
d. don't come along on my account.

Compound-word prepositions are made up of two or more words that act as adverb or those words that describe an action in terms of the setting, time, manner or frequency. The answer is C. The lightning struck from out of the blue in which the compound-word preposition is "from out of the blue"