You can round it to the nearest 10: Its closer to 90 than it is to 100, so 90 is the answer. Or you can round it to the nearest 100, its closer to 100 than 0, so 100 is the answer

The smallest number that rounds to 100 when rounding to the nearest hundred is 50. The range of whole numbers that round to 100 when rounding to the nearest hundred is 50 - 149

To round 165 to the nearest hundred, you consider if 65 is closer to 0 or to 100. Since 65 rounds up to 100, 165 would round up to 200. In contrast, if the question had been to round 140 to the nearest hundred, 40 would round down to zero, so the answer would have been 100.