The second, fifth, and eighth letters of "CARETAKER" are: A, T, and E.
Now, check for possible meaningful words using these letters:
- "ATE" (meaning "to consume").
- "EAT" (meaning "to consume food").
Hence, the first letter of the word formed is M since multiple words can be formed.
\(⇒\) \boxed{\text{Answer: M}}