The correct meaning of the underlined idiom in the given sentence is (3) Completely arranged.

The idiom "in apple-pie order" means to be in perfect order or arrangement. It is often used to describe a clean and tidy house.

In the given sentence, the speaker is saying that Shilpa cannot keep her house perfectly clean and tidy because she has two toddlers to handle and no house help.

The other options do not fit the meaning of the idiom.

• Completely messy means to be very dirty and untidy.
• Smell-proof means to be unable to let a smell escape.
• Ready for guests means to be clean and tidy enough to receive guests.