How do I answer this question "Rent paid for your home office only?"

That question would come up if you rent your home (instead of owning your home) and you have some expenses to enter that are related to only your home office as well as expenses related to the whole house.

TurboTax is asking for both the rent paid for the whole home and rent paid for only the home office.  It would be an uncommon situation for this to occur.  One example might be if your home office is actually a separate structure from your home and you pay a separate rent amount for only the home office portion.  Again, this would be very uncommon and if it did not apply to you, just leave the box blank and enter only the rent amount that you pay for the whole home.