A. AngularJS is a closed-source front-end web framework
B. AngularJS is an open-source front-end web framework
C. AngularJS is an open-source backend web framework
D. AngularJS is a closed-source back-end web framework

Solution

B. AngularJS is an open-source front-end web framework

Explanation

AngularJS is an open-source front-end web framework for constructing single-page apps based on JavaScript. The MEAN stack, which consists of MongoDB database, Express. js web application server framework, AngularJS (or Angular), and Node, uses AngularJS as the frontend.