(b) Cassini–Huygens is an unmanned spacecraft sent to the planet Saturn. Therefore, option 1 is wrong, this eliminates option (a), (c) and (d). Now we are left with final answer B only 2 and 3. MESSENGER is a robotic NASA spacecraft orbiting the planet Mercury. Voyager 1 (September 1977) and voyager 2 (Aug 1977) were launched to study the outer Solar System

The correct pairs that are matched correctly are:
b) Fructose-Glucose
c) Fructose-Galactose
d) Ribose-Deoxyribose

Let's discuss each pair in detail:

b) Fructose-Glucose:
Fructose and glucose are both monosaccharides, which are simple sugars that cannot be broken down into smaller sugar units. They are both hexoses, meaning they contain six carbon atoms.

Fructose is a ketohexose, meaning it has a ketone functional group (C=O) on the second carbon atom. It is commonly found in fruits and is known as the fruit sugar. Fructose is sweeter than glucose and is often used as a sweetener in food and beverages.

Glucose, on the other hand, is an aldohexose, meaning it has an aldehyde functional group (CHO) on the first carbon atom. It is the primary source of energy for living organisms and is often referred to as blood sugar. Glucose is found in various forms, such as in the breakdown of carbohydrates during digestion or in the form of starch in plants.

c) Fructose-Galactose:
Fructose and galactose are both monosaccharides, similar to glucose and fructose. They are also hexoses, containing six carbon atoms.

Fructose, as mentioned earlier, is a ketohexose commonly found in fruits.

Galactose, on the other hand, is an aldohexose, similar to glucose. It is less sweet than glucose and is found in various foods, including dairy products and some fruits and vegetables.

d) Ribose-Deoxyribose:
Ribose and deoxyribose are both pentoses, meaning they contain five carbon atoms. They are also monosaccharides.

Ribose is a component of ribonucleic acid (RNA), which plays a crucial role in protein synthesis and gene expression. It is involved in carrying genetic information from DNA to the ribosomes.

Deoxyribose is a component of deoxyribonucleic acid (DNA), which contains the genetic instructions for the development and functioning of all living organisms. Deoxyribose is similar to ribose, except that it lacks an oxygen atom on the second carbon atom.

In summary, the correct pairs are matched correctly because fructose and glucose are both monosaccharides, fructose and galactose are both monosaccharides, and ribose and deoxyribose are both pentoses.