Assertion (A): When we change the unit of measurement of a...

If $u_1$ and $u_2$ be the units to measure a quantity Q and $n_1$ and $n_2$ be the numerical values respectively then we know that $Q=n_1 u_1=n_2 u_2$. Since the quantity $Q$ does not change irrespective of the units used to measure it $Q=$ constant. So nu $=$ constant (\Rightarrow n \propto \frac{1}{u}) i.e., smaller the unit of measurement, greater is the corresponding numerical value.