In the play “Where’s Brownie?” what does Alex mean when she uses the expression “out of sight, out of mind"?

A.
It is better to finish a task late than not at all.

B.
When someone has done something bad to you, trying to get revenge will only make things worse.

C.
When someone or something is away, you feel more affection for them.

D.
When you can't see something, you tend to forget about it.