B. I know we have a nice little nest egg, but we're
gonna
need more money if we are going to have children.
あなたが、お金を貯めているのを知っているけど、子供を育てるに
はもっとお金がいるのよ!
【解説】
A bird makes a nesting place when it wants to have
eggs. The
nesting place keeps the eggs warm until they hatch.
In this
case, nest egg means your life savings. It is the money
you can
fall back on if you get fired from work, divorced etc...