The Owners of an Industrial Plant Want to Determine Which $H _ { 0 }$

The owners of an industrial plant want to determine which of two types of fuel (gas or electricity) will produce more useful energy at a lower cost. The cost is measured by plant investment per delivered quad (\$ invested /quadrillion BTUs) . The smaller this number, the less the industrial plant pays for delivered energy. Random samples of 11 similar plants using electricity and 16 similar plants using gas were taken, and the plant investment/quad was calculated for each. In an analysis of the difference of means of the two samples, the owners were able to reject $H _ { 0 }$ in the test $H _ { 0 } : \left( \mu _ { E } - \mu _ { G } \right) = 0$ vs. $H _ { a } : \left( \mu _ { E } - \mu _ { G } \right) > 0$ . What is our best interpretation of the result?

A) The mean investment/quad for electricity is greater than the mean investment/quad for gas.
B) The mean investment/quad for electricity is not different from the mean investment/quad for gas.
C) The mean investment/quad for electricity is different from the mean investment/quad for gas.
D) The mean investment/quad for electricity is less than the mean investment/quad for gas.