Which one of the following non-metals is not a poor conductor of electricity?

Most non-metals are poor conductors of electricity, but some exhibit semiconductor behaviour. Selenium is a well-known semiconductor that shows photoconductivity and increased electrical conductivity under excitation, which makes it markedly more conductive than typical insulating non-metals listed here [1]. By contrast, sulphur and phosphorus are molecular/insulating solids and bromine is a molecular liquid; all three behave as poor conductors under normal conditions. The general statement that non-metals are generally poor conductors (with notable exceptions such as graphite and certain semiconducting non-metals) supports selecting the semiconductor selenium as the exception among the given options [2].

Sources

1. [1] https://www.sciencedirect.com/topics/medicine-and-dentistry/selenium
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > What you have learnt > p. 55