Pls solve this puzzle fr me.?!

Pls solve this puzzle fr me.?

There are three prisoners A,B & C. A can't see B andC. C can see both A and B. B can see only C. The jailer has 5 hats - 3 red ones and 2 black ones. He asks them to close their eyes. He then places one hat on each of them and throws away the remaining two. Now he asks them to open their eyes and tells them that if any one of them finds out the colour of the hat on top of his head then all the 3 will be set free. But the time given is 1 minute. The clue is that till the 59th second no one said anything. At the last second A answered that it was a black hat on top of his head. How did he find out?

6 days ago
they can't take off their hats n c yaar pls

It was a lucky guess. Actually, I know the answer. I just can't think cause I'm listening to Master of Puppets by Metallica right now.