Which of these is most like the open architecture of the modern PC?
a. A modern car with a computer-controlled emissions system that can be adjusted by
b. A "smart" microwave with an embedded computer that allows for complex recipes and
c. A stereo system that allows speakers, disc players, and other components to be replaced
by the owner
d. A handheld computer with built-in firmware for all of the most common PDA tasks
e. A music keyboard that includes a built-in synthesizer and an LCD display