Choice A is the correct answer. Check the pattern.

1. Pattern: y is always double x.
2. Slope: $\frac{4-2}{2-1} = 2$.
3. Intercept: If slope is 2 and passes through $(1, 2)$, then $2 = 2(1) + b \rightarrow b=0$.
4. Equation: $y = 2x$.

💡 Strategic Tip: Perfect linear correlation.

Choice B is incorrect because fails $(2,4)$. Choice C is incorrect because fails $(1,2)$. Choice D is incorrect because fails $(3,6)$ ($3^2=9$).

Choice A is correct.