I.U.P.A.C., stands for?
A. Iodine Under Packing
B. International Union of Pure and Applied Chemistry
C. International Units of Protein and Carbohydrates
D. International Understanding on Physical Aspects of Chemistry

Hint: In these types of questions we should always keep our concepts clear. This is a union that provides standardisation in Chemistry.

Complete answer:
I.U.P.A.C stands for :-

I is for International
U is for Union
P is for Pure
A is for Applied
C is for Chemistry
So, I.U.P.A.C stands for International Union of Pure and Applied Chemistry

By above information, now we know that option B is correct.

Additional information
1. General reference of I.U.P.A.C:- Think about one thing, are you ready to live in society where you do not have a particular identity of yours. No person nearby knows your name. Take another case like people of your society know by you with the name ‘A’ and people of other societies know you with other names like ‘B’ ‘C’ . There will be so much confusion. So by assigning you a particular name which is done by an authorized person in our family we can be recognised by one particular name.
2. Same case happens to be with elements, molecules, organic molecules, structures. I.U.P.A.C is the authorised family of chemistry which assign names to these chemical entities present in the family of chemistry.
3. I.U.P.A.C is an association of bodies of different countries' chemical units. It is well known for publishing definitive and up-to-date data on atomic weights and isotopic abundances. I.U.P.A.C does perform its role by setting global standards for names, symbols, and units. In short I.U.P.A.C creates a common language for chemistry across different language speaking nations to remove chances of any confusion of names, standards, process.

Note: - Always try to learn I.U.P.A.C names in chemistry, because it leads to easy identification of compounds. I.U.P.A.C names tell us a lot more about the chemistry of organic compounds.