An irrational number is a type of real number which cannot be represented as a simple fraction. It cannot be expressed in the form of a ratio.
0.79 is a rational number, and options B, C and D are all rational numbers as well. when two rational numbers are multiplied by each other, the result is always a ration number too.
[tex]\begin{gathered} \text{ Option A (}\sqrt[]{7})\text{ is irrational number, when multiplied by o.79, we } \\ \text{get 0.79}\sqrt[]{7}\text{ which is an irrational number} \\ \end{gathered}[/tex]
Hence, option A is the correct option
