Answer :

To determine the rounded-off value of 98.6 to the nearest whole number, we need to follow these steps:

1. Identify the digit to the right of the unit place: The unit place here is the 8 in 98.6, and the digit to the right of it is 6.

2. Apply the rule for rounding: If the digit to the right of the unit place is 5 or greater, you round up the unit place digit; if it is less than 5, you leave the unit place digit as it is.

In the case of 98.6, the digit to the right of the unit place (which is 8) is 6. Since 6 is greater than 5, you round up the 8.

3. Adjust the unit place accordingly: Rounding the 8 up by one gives us 9.

Therefore, 98.6 rounded to the nearest whole number is 99.

So, the correct answer is:
(A) 99