In a quiz:
Q: Qui est cet homme?
A: C’est Marc Dupré.
Why C'est and not Il est?
The first rule in the lesson for C’est is that you use it if it/he/she is followed by un/une/le/la or another article. That is not the case here.
The second rule is to use C'est to express general, unspecific statements and opinions, referring to a thing generally, as in something unspecified is great or delicious, like "Science is fun!". But here, the answer is identifying a specific person, Marc Dupré, not a general concept.
Thanks.