A boy multiplied 987 by a certain number and obtained 559981 as his answer. If in the answer both 9 are wrong, but the other digits are correct, then what will be the correct?

The answer is divisible by 987.
So we can use the hit and trial method to find out the number divisible by 987 from the given choices.
553681/987 gives a remainder not equal to 0
555181/987 gives a remainder not equal to 0
556581/987 gives a remainder not equal to 0
But 555681/987 gives 0 as a remainder. Hence this is the answer