Pls answer assertion reason

Dear Student,
In order to have a straight line between P and Q, both these physical quantities must satisfy the straight line equation:
$$\begin{gathered} P=mQ+c \\ where, \\ c can be the intercept. \\ m is the slope which is cons\tan t \\ for c=0 \\ P=mQ \\ Thus, P\propto Q (\sin ce, m is a cons\tan t) \\ for m=1 \\ P=Q \end{gathered}$$
For a straight line dependence,
$$\begin{gathered} \frac{P}{Q}=cons\tan t \\ PQ\ne cons\tan t \end{gathered}$$

Thus, the statement is FALSE but the reason is TRUE.

Regards