### Solution:

Concept- Real numbers, which are separated into two categories called Rational and Irrational numbers, are one of the two types of numbers. Irrational numbers are those that cannot be represented as the ratio of two integers. The supplied numbers are rationalized because the denominator contains an irrational number, and then the two numbers are added.(a) 101 can also be written as 99 can also be written as Then will be It is in the form of which is equal to is equal to 9999

So, the correct answer is "9999.".

(b)73 can also be written as 67 can also be written as Then will be It is in the form of which is equal to is equal to 4891 .

So, the correct answer is "4891".

(c) 1010 can also be written as 990 can also be written as Then will be It is in the form of which is equal to is equal to 999900 .

So, the correct answer is "999900.".

(d) 91 can also be written as 89 can also be written as Then will be It is in the form of which is equal to is equal to 8099 .

So, the correct answer is "8099".

hence , the final answer is option 4.