Multiple dropdown selection

So Basically i have a master file data. Its being updated / added frequently horizontaly

Column A1 - Car Brand | Column B1 - Car Model | Column C1 - Serial No | Column D1 - Tire Size
A2- Toyota | B2 - Supra | C2 - 1234 | D2 - 5
A3- Nissan | B3 - ALENTRA | C3 - 6789 | D3 - 6
A4- Toyota | B4 - Corola | C4 - ab213 | D4 - 5


So i want my first drop down. select Brand. since 2 choice will be Toyota or Nissan
second drop down, if its toyota selected will display 2 choice
third box will show the specific serial number

so basically 2 dropdown which is link. display the serial number. then another separate column will show the tire size. User is only updating the master data.

i cant seem to link the car model when select the brand. how to do it? car brand should be unique choices.