At my son's high school, the catalog description of BC differs from what the counselor says is actually done. The catalog says it is a one year course that can stand alone, meaning that AB is not a prerequisite. But the counselor claims that everyone takes AB and those who go on take one semester of (I think she said) linear algebra using some MOOC and one semester of BC. I'm not overly happy about the MOOC thing, but I am happy that this school is finally giving options beyond AB.