Are there any trends for electrical conductivity?
I am unsure of how to approach this problem.


No, you are not! You have already reduced the number of candidates by good reasoning!

At this point, one 


could have a look at conductivity tables or remember in which period the metal blocks start for every main group or
remember typical electricity-related uses of $\ce{As}$ and $\ce{Sn}$


Did you ever form a conducting connection between electronic components (or just some wires) by soldering? $\Leftarrow$

(Do you recall that $\ce{GaAs}$ is used as a semiconductor material in thin film solar cells?)