The relative size of property $X$ for five elements is shown below. $P$, $Q$, $R$, $S$ and $T$ are all in Period 3 and have successive atomic numbers. The letters do not represent the real chemical symbols of the elements. Which row gives the correct answer for property $X$ and element $R$?
- Aproperty $X$: electrical conductivity; element $R$: $\text{Al}$
- Bproperty $X$: electronegativity; element $R$: $\text{Si}$
- Cproperty $X$: melting point; element $R$: $\text{Al}$
- Dproperty $X$: second ionisation energy; element $R$: $\text{Si}$