After looking at the cross sections in the photo you posted of the three bedrock outcrops, I can give you a correct answer to the question. The statement that will explain why the volcanic ask layers are good for correlating the ages in the three outcrops is that the ask was deposited over a large area when a volcano erupted in the past. You can see in the picture that there is fossils, you can see that there are not ask found between many of the layers of bedrock and the you can also see from the picture that it didn't occur over a long period of geologic times. This is why you can be sure that the 1st statement is the correct statement, by ruling out all the other choices. The correct choice is number 1.
