How do I figure out the capital gain on my vehicle that was totaled when my business mileage varied from year to year?

My car was totaled in 2018. I used the car for two of my rental properties since 2013, and also for personal uses. I will put some fake numbers here for simplicity:

In 2018, the total miles on the car is 4000, with 1000 miles for property A and 2000 Miles for property B, so the business portion for A is 25%, for B is 50%, and for personal is 25%.

The FMV for the car when it is used for business in 2013 say is: $5000

I used the standard mileage from 2013 to 2018.

the depreciation equivalence for car A = $2000, the depreciation equivalence for car B = $2000

In 2018, when the car is totaled, insurance paid us $2000. Here are my questions:

1) in Form 4749, how do I fill the sale price for the car under each property?

is it for property A, the sale price for the car is $2000*25%=500 (because the interview ask to put the business portion of the sale price)

for B the sale price for the car = 2000*50% = $1000?

But if that is the case, how can the sale price the same car be different?

2) In form 4749, how do I fill the cost base for the car under each property? The business percentage change each year

3) How do I figure out the depreciation for the car under each property?

I thought it should be $2000 under property A, and $2000 under property B because that was their depreciation equivalence.

I could not figure out how the Turbo Tax allocates the cost base for the car under property A or B on 4749

Please help! Thanks, --Li