Why isn't the 3rd choice correct in the following exercise?


In the following exercise (JLPT, level N3, reading comprehension):

[![enter image description
here](https://i.stack.imgur.com/vXGma.jpg)](https://i.stack.imgur.com/vXGma.jpg)

The correct answers are 1,4,5.

I want to ask about the answer #3. I translated

> このマンションを借りる場合、敷金は3か月前に払わなければならない

as

> To rent this mansion, you have to pay a security deposit 3 months in
> advance.

And I want to know why 3 isn't correct. I think the answer 3 is correct too,
because there's a quote of 夫 saying

> 敷金は **3か月** 分だけれど

which I translated to

> The security deposit is an amount of 3 months

Doesn't「敷金は3ヵ月分」mean the same as「敷金は3か月前に払わなければならない」 ?




In the text you have:

[code]

    三ヶ月分
    
[/code]

which means, "the equivalent of three months (of rent)", where the (of rent)
part is understood from context. The keyword here is 分.

In the question you have:

[code]

    三ヶ月前に払わなければならない
    
[/code]

which means, "have to be paid three months in advance". The keyword here is 前.

The text states nothing about **when** the security deposit has to be paid,
only that the amount is the equivalent of three months of rent. The question
3, that is incorrect, states that the security deposit has to be paid three
months in advance, that is, three months before moving in.




In the text you have:

[code]

    三ヶ月分
    
[/code]

which means, "the equivalent of three months (of rent)", where the (of rent)
part is understood from context. The keyword here is 分.

In the question you have:

[code]

    三ヶ月前に払わなければならない
    
[/code]

which means, "have to be paid three months in advance". The keyword here is 前.

The text states nothing about **when** the security deposit has to be paid,
only that the amount is the equivalent of three months of rent. The question
3, that is incorrect, states that the security deposit has to be paid three
months in advance, that is, three months before moving in.

