Spoiler | pp2 tc

This blank is a support, because of the colon, the second sentence seems that it means that the journalists support each other.
So I thought B and E, but the answer given is A and D,
How is A and D the answer, i dont understand how check on and brake on is a synonym or what they really mean.

Can someone help please ?

The RHS doesn’t quite say that, it says that they checked each other’s work and stopped each other from publishing if they felt it wasn’t ready.