Answer:
Mold b will use the least amount of wax.
Explanation:
The formula for volume is :

Mold A :
r = 1 in
h = 7 in
V =
cubic inches
Mold B :
r = 1 in
h = 4 in
V =
cubic inches
Mold C :
r = 1.5 in
h = 3 in
V =
cubic inches
Mold D :
r = 2 in
h = 3 in
V =
cubic inches
Now comparing the volumes of all the molds, we can see that the volume of mold B is the least. This means it will use the least amount of wax.