Which Best Describes the First Law of Thermodynamics

Which best describes the first law of thermodynamics?

A) Energy is changed from one form to another with a loss of usable energy.
B) Energy is not created nor destroyed, but it can change from one energy form to another.
C) Energy can be created from matter or used to produce matter.
D) Some useful energy is lost as heat whenever an energy transfer occurs.
E) Energy transfers are always 100% efficient in changing energy from one useful form to another.