What is the myth of the central channel? I- A central channel is a sum of the left and right channels. II- A good processor should remove common c...

What is the myth of the central channel?

I- A central channel is a sum of the left and right channels.
II- A good processor should remove common cuts from L and R to leave the central channel only responsible for the frequencies in the center.
III- A central channel is what is common up to a certain level in L and R, but not the sum.
IV- A central channel is a complicated issue and should be a primary item when establishing a scenario.
a) I and IV are correct.
b) II and III are correct.
c) III and IV are correct.
d) I and III are correct.