Today's answer is C; the telephone is still widely used and so not obsolete. The telegraph was eventually replaced by digital data transmission, the steam locomotive was superseded by those powered by diesel fuel and electricity, and you can ask your parents about eight-track tapes! The word "obsolete" is of Latin origin. It traces to the Latin "obsoletus," a form of the verb "obsolescere," meaning "to grow old, become disused." English speakers adopted "obsoletus" as "obsolete" in the 1500s. "Obsolete" first appeared in print in the mid-1500s and it shows no signs of becoming outmoded.