Consider the following types of vehicles : I. Full battery electric vehicles II. Hydrogen fuel cell vehicles III. Fuel cell-electric hybrid vehicles How many of the above are considered as alternative powertrain vehicles?

All three are correct because alternative powertrain vehicles encompass any technology—including battery electric, hydrogen fuel cell, and their hybrid combinations—that replaces the traditional internal combustion engine (ICE) powered solely by fossil fuels. Option (B) is the most tempting error if one mistakenly believes "hybrid" only applies to conventional petroleum-electric vehicles, whereas fuel cell-electric hybrids are a distinct class of advanced alternative propulsion. The core concept tested is the classification of green transportation technologies and their role in decarbonizing the automotive sector.