What is one of the key (important) parts of photographing people?

motion
lighting
lines
all of the above

All of the above                                                        

answer: the feeling it gives you when you look at it.

explanation:

in every single medium of art, you are supposed to feel something that makes it art. like how a song can make you cry, or how a photograph can make you nostalgic. art is very important for expressing yourself as well, when you are happy, sad, depressed, or angry.