Answer:
C.
Step-by-step explanation:
In 1837, when Samuel Morse had an idea of making electric telegraph worked, he faced with a challenge to push forward the signal across long distance. They knew that sending legible signal across the continent would be difficult. So, Morse attached a relay to his device that will work like a relay horse, sending forward the signal by taking message from the exhausted partner and push it with renewed vigor.
So, the correct answer is option C.