Answer:
B) Their valence shell is full
Explanation:
In order to be classified as a noble gas, an element must have a complete octet/ a full shell of valence electrons, as shown in answer B.
A and C are just incorrect. Since noble gasses are very unstable, D is a true statement, but is isn't the correct answer as this does not explain why they are inert.
<h3>Hope this was helpful!</h3>
The circulatory system picks up nitrogenous wastes from the cells and delivers them to the kidneys. The kidneys remove these wastes from the blood and concentrates them into the urine that is eliminated from the body.