Erin Runs a Cookie Store in Rhode Island

Erin runs a cookie store in Rhode Island. After raising the price from $1 to $2 per cookie, her total revenue from selling cookies per week decreased from $200 to $150. Thus, it can be said that the demand for Erin's cookies is:

A) perfectly inelastic with a price elasticity of demand equal to zero.
B) elastic with a price elasticity of demand greater than one.
C) unit elastic with a price elasticity of demand equal to one.
D) inelastic with a price elasticity of demand less than one.
E) perfectly elastic with a price elasticity of demand equal to infinity.