Question

What is the meaning of the adage "Save it for a rainy day"?

A.
Do chores on days when it rains.

B.
Save your money for when you'll need it.

C.
You'll appreciate things more when it rains.

D.
People don't do much on rainy days.

Answer 1

B. Save your money for when you'll need it.

Answer 2

i would go for B save your money for when you'll need it. 
the saying "save it for a raining day" is pretty much saying, that the when the rainy day, is the day you'll need the money, example is when you need to pay off them Yakuzas before they  take you out.

lol sorry for the bad explanation