Final answer:
The correct order from least to greatest is 7, 8, √68, 9. Given that √68 is between 8 and 9, the sequence matches choice D.
Step-by-step explanation:
To order the numbers from least to greatest, we first need to evaluate the square root of 68. While it's not a perfect square, we can approximate its value or find its value using a calculator. The square root of 68 falls between the square roots of 64 (which is 8) and 81 (which is 9), so it will be a little more than 8. Therefore, we can order the numbers as follows: 7, 8, √68, 9. The correct sequence according to the options provided is thus 7, 8, √68, 9, which is Choice D.