I am having some trouble answering this multiple choice question on a graph and have posted the question with my thoughts below.
Thank you very much.
Given correct answer (hidden in white): D
My thoughts: According to the question, y-axis = (Northern Ireland house price) average of United Kingdom's house prices.
A: I eliminated this choice since the change in the graph from 1980-1986 can be due to an increase in the UK average (and not necessarily a decrease in NI prices).
B: I ruled out this option since the ups and downs could be caused by changes in the UK average (Certainly, the NI price could have even remained constant).
C: I eliminated this choice because NI house prices could have decreased, which would explain the overall ratio's decrease in 1986.
D: I ruled out this statement since the increases in the graph can follow from a decrease in the UK average, and not necessarily a rise in NI's prices.
E: I decided against this choice, using the same reasoning as for choices A to D above.
Where did I err?