To answer this question, you need to understand that POS is an acronym that stands for "Point Of Sales".
Let's go through each option to understand why it is correct or incorrect:
Option A) Personal Operating system - This option is incorrect because the correct full form for POS is "Point Of Sales", not "Personal Operating system".
Option B) Ping On Top - This option is incorrect because the correct full form for POS is "Point Of Sales", not "Ping On Top".
Option C) Point Of Sales - This option is correct. POS stands for "Point Of Sales", which refers to the place where a transaction or sale takes place.
Option D) Put In Open - This option is incorrect because the correct full form for POS is "Point Of Sales", not "Put In Open".
The correct answer is C) Point Of Sales. This option is correct because it accurately represents the full form of POS.