What is NOT a Category of Higher Education Institutions?

While the following are considered categories of higher education institutions -

A. a university and the four-year undergraduate institution --- the college B. the technical training institution C. the two-year community college D. graduate school

... there is one type that doesn't quite fit:

E. vocational schools

Vocational schools, while offering specialized training, are typically not considered part of the traditional higher education system. They focus on practical skills and career readiness, often with shorter programs compared to degree-granting institutions.