Answer:
24 oz has the lowest cost per ounce.
Explanation:
12 oz ---> $2.49
1 oz --> $2.49/12
1 oz --> $0.2075
14 oz --> $3.15
1 oz --> $3.15/14
1 oz --> $0.225
20 oz --> $5
1 oz --> $5/20
1 oz --> $0.25
24 oz --> $4.56
1 oz --> $4.56/24
1 oz --> $0.19 ..........this is the lowest cost per ounce
36 oz --> $7.2
1 oz --> $7.2/36
1 oz --> $0.2