Final answer:
A negative balance in Luiza's bank account means that she has overdrew her account by 87.12 rubles.
Step-by-step explanation:
The negative balance of -87.12 rubles in Luiza's bank account means that she has overdrew her account. This means that she has spent more money than she had in her account, resulting in a negative balance.
To better understand this, consider if Luiza had 100 rubles in her account and she made a withdrawal of 200 rubles. This would result in a negative balance of -100 rubles because she withdrew more money than she had in her account.
Therefore, option A is the correct answer: Luiza overdrew her account by 87.12 rubles.