We want to compare averages. From the histogram we have we don't know the exact mean, but if we just assume the average in each bin is the midpoint of the bin we can make an estimate.
Supplier A has
mean = ( 22(64) + 27(66) + 26(68) + 15(70) + 10(72) )/(22+27+26+15+10)
mean = 6728/100 = 67.28 grams
Supplier B has mean 66.5
Answer: Choose Supplier A
(work shown above)