It is given in the question that "floating point numbers are represented with $32\ bits$"

so from 32 bits we can get $2^{32} = 4, 294 , 967 , 296$ = total $10$ digits in decimal .

**that means 32 bits are equal to 10 decimal digits**.

$A = 2.0 \times 10^{30}$ this represents 31 digits and $C = 1.0$ this is 1 digit.

So $A+C = total\ (31+1) = 31$ digits.(addition in decimal)

A is one 2 followed by thirty 0's = 31 digits and C is 1 digit.

**This 31st digit is outside the precision level of A**.

As we need to do $Y = A + C$, so it does not take the value of $C$.

**Y = A **is assigned and at max, it takes **10 digits** and rest are **overflow** that's why this addition only return value of A, **one extra digit it cannot take**

This addition will return the value of A which will be assigned to Y.

So $Y = A+C = A$

and $Y = Y + B = ( 2.0 \times 10^{30} ) + ( - 2.0 \times 10^{30} ) = 0 .0 $

$X = A+B = ( 2.0 \times 10^{30} ) + ( - 2.0 \times 10^{30} ) = 0 .0$

and $X = X+C = 0.0 + 1.0 = 1.0$

$\therefore$ $B$ is the correct option.