Who designed the pendulum clock? A. Galileo Galilei B. Thomas Alva Edison C. Frederick Jones D. Davidson

Galileo Galilei studied pendulums and designed a pendulum-controlled clock around 1641, though he died before it was built. The first working pendulum clock was made by the Dutch scientist Christiaan Huygens in 1656, who is not among the options; that is probably why the question was dropped.