Shania is trying to determine the oldest geologic unit on this map.She is unable to do so as there is no key on the map.Thus the correct answer is B.
What is a Map?
A Map is a graphical representaion of area which is an individual used travel to complete their journey with the help of it.These also helps to identify the feature like sea route, rail route, rivers, winds or oceans land in the area.
Shania is trying to determine the oldest geologic unit on this map but she was unable to it as there is no information given on the map.There is no key value whic helps to identify the location or geologic unit.
Therefore, option B There is no key on the map is the approparite answer.
Learn more about maps, here:
https://brainly.com/question/1565784
#SPJ5