I want to know the answer to the following question:
Which generation of PowerBooks introduced trackpads?
All the background I'm provided with is that "Although due to considerable design issues, it was soon replaced in 1991 with the first of the PowerBook line: the PowerBook 100, a miniaturized portable; the 16 MHz 68030 PowerBook 140; and the 25 MHz 68030 PowerBook 170.". Is that enough to answer the question?