Answer:
A. √57
Explanation:
√47 would be off the number line because it's below the number 7
√65 would be past 8 but the red dot comes before the number 8
√72 would be past 8 as well and it would be past √65 but the dot is before number 8
This leaves our answer as √57 beause the square root of 57 is 7.549 (etc.) which is between the numbers 7 and 8, while also being slightly higher than 7.5 :)
Have a good day!