The table provides details for four elements, P, Q, R and S, including melting point in $^\circ\text{C}$, electrical conductivity of the element when solid, density in $\text{g cm}^{-3}$, and the colour of the iodide of the element. Which elements could be transition elements?
- AP, Q and S
- BQ and S only
- CR and S only
- DS only