What are the cabinets? Is the top in place? There;s no way to select here, or on the internet.

You go to the local tile shop, and you drag home the samples and you stand them up. You ask yourself do you like it? Or you sample FROM the internet and stand them on the counter, in your lighting, with your cabinetry. You don't get hung up on paying for shipping for the one you love, when you've put marble in the kitchen and the labor will be the same whether you select one you love, or one you merely settle on.

You ask yourself if you want to rip it off and redo it if you hate it!

You have no information, no pictures and marble comes from the earth, no matter which marble and all of them can be very "different" despite commonality in name. So.......we can not help you: )

There about 80 million white, 3 x 6 subway tiles........maybe more. Shop it locally.

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There are so many options out there, but you do need to get local samples to try in place but only AFTER the countertops are installed. Backsplash should be the very last thing you choose. Are you hung up on 3 x 6” size tiles? Because a lot of the options out there now are more like 2 or 2 1/2” x 8”. Lots of options out there for $12 -15/sq. ft. Go to tile stores, look around for options. If you have a countertop sample, take that with you, but don’t decide until you can take samples home and see in place with your lighting and countertop in place.

If you don't like solid white, consider a crackle finish. But, yes, there are thousands of white rectangular tiles, and you need to look for yourself.

There are a million options between subway tile from $ to $$$$. You need to go to a better tile showroom in your area and see what appeals to you. I suggest shopping with cabinet color and counter if possible or good photos to start.

I do not like white subway tile with Cararra marble I usually use a gray with matching grout the gray the same as the gray in the marble . There is no way to help with colors on a monitor ever.