Those who have visited the Grand Canyon have typically seen layers of sediment in the gaping canyon, with different colors that mark the passage of time like the rings in a tree trunk.

(A) seen layers of sediment in the gaping canyon, with different colors that mark
(B) seen layers of sediment in the gaping canyon, whose different colors mark
(C) been seeing layers of sediment in the gaping canyon, whose different colors are markers of
(D) been able to see layers of sediment in the gaping canyon, with different colors marking
(E) seen layers of sediment in the gaping canyon, marking by different colors

The OA is A
I understand B is wrong here.
OE says that in B it's not clear whether "whose" refers to "canyon" or to "layers"
It may sound dumb, I am not very well convinced with it.
I think it should refer to layers as layers are having different colours.But ultimately layers are a part of canyon.
So it is ok I guess.