LoL. I don't recollect seeing an American ever write it with a C.
A look at Merriam-Webster online shows confusion, in that practice appears to be shown shown with either spelling for any usage. A bot like Peter Bozz's finding in the American Heritage Dictionary.
However, the Oxford makes the correct way clear:
Now, whether Americans can spell properly? That I can't answer...probably no more or less than anybody else in the English-speaking world. But they do spell some things differently, uniquely so because the rest of them (South Africa, AU, NZ etc) follow UK. Canada is supposed to, too, but obviously cannot escape the pervasive influence of its southern neighbour, and so tends to follow US norms.
And if you are in business in CA it is even harder e.g. with measurements. Although CA is metric anything supplied to the US has to be Imperial/American standard, so people get wrapped up in this and forget metres and litres...
DAS
For direct contact replace nospam with schmetterling