Ideal gas equation

$\frac{PV}{T} = constant;$

$PV$ is not constant on $T$

When $P$ is constant $V \propto T$ so $V, T$ graph is a st.line as $V$ increases $T$ increases.

When $T$ is constant $P \propto \frac{1}{V}$ is not a st. line

$\therefore (A) $ is correct answer.