two graphs are shown below:

graph a shows scatter points 1, 3 and 2, 5 and 3, 7 and 4, 9 and 5, 11
graph b shows scatter points 1, 11 and 2, 9 and 3, 7 and 4, 5 and 5, 3

which scatter plot shows a linear relationship between x and y?

only graph a
only graph b
both graph a and graph b
neither graph a nor graph b