Grid lines to the right represent positive numbers for the first coordinate. 3 of them will put you on a grid line with a value of 3×0.5 = 1.5.
You now know enough to select the correct answer, ...
... (1.5, -2.5)
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You can confirm this is the correct answer by figuring the second coordinate. Down represents negative numbers, so down 5 units is -(5×0.5) = -2.5. This matches the second coordinate of the chosen answer.