Toss Up - General Science - Multiple Choice

Which of the following is NOT true regarding the burning of biodiesel versus gasoline in automobile engines:
W) biodiesel combustion does not emit SO2
X) biodiesel contains more oxygen than gasoline
Y) the CO2 released when biodiesel is burned is the same CO2 the plants removed from the atmosphere as they grew
Z) the energy content per gallon of biodiesel is approximately 28% lower than that of ethanol