When you resize the Amazon RDS DB instance, Amazon RDS will perform the upgrade during the next
maintenance window. If you want the upgrade to be performed now, rather than waiting for the maintenance
window, specify the ____ option.

A.
ApplyNow

B.
ApplySoon

C.
ApplyThis

D.
ApplyImmediately

Explanation:
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.DBInstance.Modifying.html