The performance of a diesel engine with blends of biodiesel fuels was the topic of research in the International Journal of Energy and Environmental Engineering (Dec. 2013). Several of the many variables measured in the study are listed below. Identify the type (quantitative or qualitative) of each variable.

a. Diesel fuel type (HSD, MO, MB100, SRO, or B20)

b. Water content (parts per million)

c. Flash point temperature (degrees Centigrade)

d. Fuel density (kilograms per cubic meter)

e. Location of soot deposits (cylinder head, piston crown, or fuel injector)