Cel animation, and live footage of people or are usually combined together on the computer using footage in front of a
a. (1) pyrotechnics; (2) stunt actors; (3) screenshot
b. (1) cgi; (2) miniatures; (3) green screen
c. (1) rotoscoping; (2) animated footage; (3) projector
d. (1) makeup; (2) puppets; (3) composite screen

The correct answer is letter B. (1) CGI; (2) miniatures; (3) green screen.
CGI, cel animation, and live footage of people or miniatures are usually combined together on the computer using footage in front of a green screen.

The correct answer is b. (1) CGI; (2) miniatures; (3) green screen.  

The complete answer would be: CGI, cel animation, and live footage of people or miniatures are usually combined together on the computer using footage in front of a green screen.

In this case,

CGI stands for Computer-Generated Imagery, which refers to the application of computer graphics to special effects. Miniatures, or a miniature effect, refer to a special effect that is created with the use of scale models. Green screen refers a visual effects technique in which two images or video streams are layered together. In the past, a blue screen was used, but with the rise of digital filmmaking, now the green screen is preferred.