The correct answer is (A) To keep (under control, in possession, in mind, in place, etc.); to hold (in place or position); to continue to (use, practice, etc.). Also, to secure the services of (especially by an initial fee)

Retain comes from Old French retenir, Latin retinere.

Examples of use:

• This material will not retain its color if washed
• Although apparently retired, he has retained his directorships.