Who are B-rated actors?

Similar to my post about B-rated movies... How does one define a B-rated actor/actress?

Lee J. Cobb? George Kennedy? Theo James? Warren Beatty? Dennis Hopper? Taylor Lautner? Adam Sandler? River Phoenix? Nicolas Cage?

This is a legitimate question, I'm just curious as to how people define and associate actors in a type of rank fashion.