Estimate the number 7458 to its nearest hundred.

To round off a number to the nearest hundred, we have to look at the tens digit of the number. If the tens digit is 5 or more, we have to add 1 to the hundreds digit and replace all digits after the hundreds place with 0s. If the tens digit is less than 5, we have to replace all digits after the hundreds place with 0s.

Here, the tens digit of 7458 is 5, equal to 5. Therefore, to round off 7458 to the nearest hundred, we have to add 1 to the hundreds digit and replace all digits after the hundreds place with 0s.

So the answer is 7500, which is option B.