Question

the child is afraid _____darkness (preposition)​

Answer 1

The child is afraid of darkness.

The use of prepositions in English Grammar

• Prepositions are 150 common words that are used as connectors to connect nouns and proper nouns with other parts of the sentence.
• Prepositions play a vital role to complete the structure of the sentence.
• We add these words before nouns, and proper nouns to establish a link with other parts of the sentence.
• Some examples of prepositions are from, upon, by, etc

So the correct answer will be of.