c - CVT
CVT (Continuously Variable Transmission) - This is similar to an automatic gearbox in that there is no clutch to depress. However, unlike a normal auto, there are no gears.
A CVT transmission has two cones inside - one connected to the engine, the other to the driven wheels - with expandable bands between them. As these cones move alongside one another they continuously vary the gear ratios.
A CVT gearbox revs the engine to its peak pull when the accelerator is pressed hard, so the engine gives maximum shove straight away rather than building up to it. Cars with CVT gearboxes also achieve better fuel economy than regular automatics and emit less carbon dioxide.