Answer:
B. Over estimate
Explanation:
11/9 + 3-6/7 in comparison to 1+4=5
11/9 + 27/7 = 77/63 + 162/63 = 239/63 = 3.79
So 5-3.79=1.21 difference so it was an overestimate by 1.21
Had they chosen 4 we could have considered that a close guesstimate but 5 is too far over of an estimation
Hope this helps.