Think of any number divisible by 4. It can be 988, 984 or else. Add it to 105 then if you think it's the largest three-digit whole number on the sequence, then it's the answer to your question.
105 + 988 = 1093 - It's already 4 - digit number.
105 + 904 = 1009 - still a 4 - digit number.
105 + 892 = 997 - it's a 3-digit number. Just simply add 3 to it and it will become 4 - digit, so that, it's the largest three-digit number in the sequence.
Therefore, the answer to your question is 997.