Article and preposition for foreign universities

I'm curious as to what article/preposition one should use to refer to studying at a university, such as Stanford University (in the USA).

Which ones are correct if I want to say "I study at Stanford (University)"? Should I use an or bei, and should I put in a definite article or not?

(a) Ich studiere an Stanford.

(b) Ich studiere bei Stanford.

(c) Ich studiere an der Stanford Universität.

(d) Ich studiere bei der Stanford Universität.

• (d) is also wrong. The word order in (c) seems unnatural in German (at least to me), you'd rather say Ich studiere an der Universität Stanford. In any case you'd have to add a hyphen in writing: Ich studiere an der Stanford-Universität. Alternatively you may keep the original as it's a proper name: Ich studiere an der Stanford University. – collapsar Mar 21 '14 at 15:51