Ans: A
The diagram of A shows the relation that $y$ increases when $x$ increases.
The diagram of A shows the relation that $y$ increases when $x$ increases.
The diagram of B shows the relation that $y$ decreases when $x$ increases.
The diagram of C shows no relation between $x$ and $y$.
The diagram of D shows the relation that $y$ keeps constant when $x$ varies.
