Answer:
Option C.
Step-by-step explanation:
We know the following properties,
1. Product of an irrational number and a non-zero rational number is always an irrational number.
2. Sum of a rational and an irrational number is always an irrational number.
3. Sum or products of rational numbers are always a rational number.
In option A,
[tex]4\frac{2}{3}+\frac{\sqrt{3}}{9}[/tex]
Here, [tex]\sqrt{3}[/tex] is an irrational number.
[tex]\frac{\sqrt{3}}{9}[/tex] is an irrational number using property 1.
[tex]4\frac{2}{3}+\frac{\sqrt{3}}{9}[/tex] is an irrational number using property 2.
So, using the above properties we can say that this expression represents an irrational number.
Similarly,
In option B,
[tex]4\frac{2}{3}\times\frac{8}{\sqrt{3}}[/tex]
Here, [tex]\sqrt{3}[/tex] is an irrational number. So, using the above properties we can say that this expression represents an irrational number.
In option C,
[tex]4\frac{2}{3}-\frac{\sqrt{4}}{8}[/tex]
Here, [tex]\sqrt{4}=2[/tex], which is a rational number.
So, this expression represents a rational number using property 3.
In option D,
[tex]4\frac{2}{3}\times\frac{\sqrt{3}}{9}[/tex]
Here, [tex]\sqrt{3}[/tex] is an irrational number. So, using the above properties we can say that this expression represents an irrational number.
Therefore, the correct option is C.