The can of green beans that has the lowest unit price is the 8 oz. size.
To find the unit price of each size, divide the cost by the size. (A number below that's in parentheses means it goes on forever)
0.89 ÷ 6 = 0.148(3)
1.04 ÷ 8 = 0.13
1.69 ÷ 10 = 0.169
4.79 ÷ 32 = 1496875
Among all of these answers, the can with 8 oz. has the least unit price/rate. Thus, this is the answer.