You received a new wallet for your birthday and it came loaded with some cash. You keep daily data for the amount of money in your wallet, and you found that the data could be modeled by a linear function with a negative slope where y represents the amount of money in your wallet and x represents the number of days since your birthday. Based on this information, which of the following statements could be true?
Select all that apply.

A You have not been taking any money out of your wallet.

B You have been using the money in your wallet to buy coffee each morning.

C You have been spending some of your birthday money.

D Some friends have given you belated gifts of money that you put into your wallet, and now you have more than you started with.