Answer:
By.
Step-by-step explanation:
A preposition can be defined as a word that shows or illustrates the relationship between a pronoun or noun and other words in a sentence. Some examples of a preposition is up, below, after, by, against, for, over, etc.
The most appropriate preposition to be used in the sentence is "by."
I shall send you this CD latest by 10 February.
Basically, it means the CD would be sent before a specific time or before the end of a specific period of time i.e a given time interval.