Answer: pages

Explanation:
The necessary part of a book is its pages; there is no book without pages. Not all books are fiction (choice a), and not all books have pictures (choice c). Learning (choice d) may or may not take place with a book

Answer: strings

Explanation:
A guitar does not exist without strings, so strings are an essential part of a guitar. A band is not necessary to a guitar (choice a). Guitar playing can be learned without a teacher (choice b). Songs are byproducts of a guitar (choice c)

Answer: aged

Explanation:
An antique is something that belongs to, or was made in, an earlier period. It may or may not be a rarity (choice a), and it does not have to be an artifact, an object produced or shaped by human craft (choice b). An antique is old but does not have to be prehistoric (choice d)

Answer: dwelling

Explanation:
A domicile is a legal residence, so dwelling is the essential component for this item. You do not need a tenant (choice a) in the domicile, nor do you need a kitchen (choice c). A house (choice d) is just one form of a domicile (which could also be a tent, hogan, van, camper, motor home, apartment, dormitory, etc.). 

Answer: directions

Explanation:
A recipe is a list of directions to make something. Recipes may be used to prepare desserts (choice a), among other things. One does not need a cookbook (choice c) to have a recipe, and utensils (choice d) may or may not be used to make a recipe.

Answer: seat

Explanation:
A saddle is something one uses to sit on an animal, so it must have a seat (choice b). A saddle is often used on a horse (choice a), but it may be used on other animals. Stirrups (choice c) are often found on a saddle but may not be used. A horn (choice d) is found on Western saddles, but not English saddles, so it is not the essential element here.

Answer: None of these

Explanation:
There is no explanation...

Answer: MBBS Degree 

Explanation:
There is no explanation...

Answer: None of these 

Explanation:
There is no explanation...

Answer: Cocoa powder 

Explanation:
There is no explanation...

Answer: Corruption 

Explanation:
There is no explanation...

Answer: Fruit pulp 

Explanation:
There is no explanation...