Your answer would be A. "The money is available for an emergency". This is because you are not touching that money so, you are saving overtime and while your money is sitting in that account it gains a small percentage over time.
It could not be the other answer choices because, the money tripling and doubling over a short period time is an investment. Savings accounts are long term so you gain money over time. The account is not riskier than stocks because dividends are guaranteed and you're not losing your money.