Antonym of RETAIN

Answer: Option C

Retain : continue to have (something); keep possession of.
Reject : dismiss as inadequate, unacceptable, or faulty.
Renounce : formally declare one's abandonment of (a claim, right, or possession).
Spare : make free or available.
Eject : force or throw (something) out in a violent or sudden way.

Antonym of Retain is Spare