I think it is B) red roses are associated with romance
Explanation:
One way to use slang and idioms in a story is to make characters feel more natural and funny. Unless a character is very formal, real people would not talk without slang or idioms.
Buying things on easy instalments can keep you permanently in debt but if you have a regular salary or wages this may be the best way to spread out your debts. On the other hand, if you are a consultant or contractor and don't get regular income, it becomes necessary to pay some things with a lump sum as much as possible in the absence of regular income.
An author can express his views through tone.
