Group 0 - they are called the NOBLE GASES
(as they're very unreactive) because...
ALL of their atoms are full.
Example : Helium contains 2 electrons so it's outer shell is full
(d) option is right answer
Answer: Option (c) is the correct answer.
Explanation:
The difference in electrical potential energy between two places in an electric field is known as potential difference.
Mathematically, potential difference between two given points can be written as follows.

where,
= potential difference
= potential at point 1
= potential at point 2