Rewrite the sentence in active voice.
A children's story is written by Amith.

Correct option is C

Explanation: The passive voice sentence "A children's story is written by Amith" indicates a simple present action, which in active voice aligns most accurately with "Amith writes a children's story."
Conversion Rule: Present indefinite
Subject + verb + object -> <- Object + auxiliary verb (is, am, are) + past participle + by + subject.
Example: The song was written by John. -> John wrote the song.