I would like to see how this problem is worked out please, i try to do the problem but i dont get any of the awnsers, ive been told its B but i cant

I would like to see how this problem is worked out please, i try to do the problem but i dont get any of the awnsers, ive been told its B but i cant get that awnser:

Thompson seedless grapes prices decreased from$500/ton to $250/ton which resulted in grape growers decreasing the quantity they supplied from 500,000 tons to 400,000 tons. the elasticity of supply over that range of prices is

a.)0.11

b.)0.33

c.)0.66

d.)1.11

e.) cant be determined from the available info