ANS:D - are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron.

The statement you provided describes metalloids accurately. Metalloids are elements that exhibit properties of both metals and non-metals to varying degrees. Here's how each point in your statement aligns with the characteristics of metalloids:

1. Good conductor of heat & electricity: Metalloids indeed can conduct heat and electricity, but not as efficiently as metals. They generally have intermediate conductivity between metals and non-metals.
2. Act as electron donors with metals & as electron acceptors with non-metals: Metalloids can exhibit properties of both metals and non-metals in chemical reactions. They can either donate or accept electrons, depending on the specific elements involved and the chemical environment.
3. Not necessarily solids at room temperature: While many metalloids are indeed solid at room temperature (e.g., silicon, germanium), some, like arsenic and antimony, can exist in various physical states, including solid, liquid, or gas, depending on temperature and pressure conditions.
4. Compounds that exhibit both metallic & non-metallic properties and are exemplified by elements like germanium, silicon & boron: Germanium, silicon, and boron are classic examples of metalloids. They show properties intermediate between metals and non-metals. For instance, silicon is a semiconductor and exhibits both electrical conductivity (like metals) and the ability to form covalent bonds (like non-metals).