There has never been a bank account with complex numbers representing the balance or any entry. (4) is not the answer. I've only seen my bank balance = a whole number once and we have several accounts. 2 and 3 are possible but highly unlikely. The numbers are real, but let's hold off answering (1). The answer is likely (5) because all bank entries are going to be able to be expressed as a decimal. So I would pick 5 over 1.
The amount of money in a bank account would be a whole number if you don't owe money. Whole numbers are complete numbers like 1,2,3,4,5, etc. 1.2,3.4,4.5, and other decimals are not whole numbers. Your answer would be whole numbers.
