Concept:The sentence needs the superlative form of the adjective "early" to show comparison among more than two times.
Explanation:The positive degree is "early".
The comparative degree is "earlier".
The superlative degree is "earliest".
When we compare the time of submission with all other submission times in the past, we use the superlative form.
Therefore, "earliest" is the most appropriate choice.
The word "later" is comparative, "lately" is an adverb meaning recently, and "early" is not in the superlative form.
Answer:C. earliest