When the price of cell phones decreased from $16 to $12, production decreased from 2,500 to 1,200 per month.

When the price of cell phones decreased from $16 to $12, production decreased from 2,500 to 1,200 per month. You can conclude that the supply of cell phones is price (indeterminate/ elastic/ inelastic). 

When the price of cell phones decreased from $18 to $12, production decreased from 2,000 to 1,200 units per month. 

The price elasticity of supply is 

(0.8 / 0.4 / 1.25/ None of the above)