Usted Capitalized in Quiz

Question

In the quiz the answer was con Uds but I chose what I knew wasn't the right answer ustedes because the Uds would be  capitalized in the middle of the sentence. I'm pretty sure that's not correct either. Anyway, I don't think we need these kind of trick questions. My thought is that is a poorly created test question. That said, I'm interested if one ever capitalizes Uds in the middle of a sentence or if the capitalized Uds is standard for the abbreviation of usted and I am wrong here.

Accepted Answer

Hola David
The RAE recommends to use the whole word in lower case: usted / ustedes, but they also accept the abbreviation Ud. / Uds. written with an initial capital letter. The reason for this is to not get it mixed up with another abbreviation used in lower case to indicate "unidad" (unit/units) which is "ud." and "uds." used when you're talking about quantities.
I hope this clarified it.
Saludos cordiales 
Inma