4 batches: 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 = 4 4/4 = 5
6 batches: 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 = 6 6/4 = 7 1/2
7 batches: 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 = 7 7/4 = 8 3/4
8 batches: 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 + 1 1/4 = 8 8/4 = 10
The answer is C because 8 batches needs 10 cups of flour, and 7 batches is closest to 9 cups than 6 batches.
You can also look at it like this:
1 1/4c ≤ 9 (c is # of cups)
Or you could have multiplied 4, 6, 7, 8 to 1 1/4 or 1.25
