William Harvey, an English physician, was the first to correctly and completely describe how blood circulates through the heart and body in the 17th century. The other scientists are known for the telephone (Graham Bell), computers (Babbage), and the light bulb (Edison). So the correct answer is William Harvey, option (3).
PRO TIP
Re-check your working by substituting the answer back into the original question.
During a thunderstorm, the sound of thunder is heard 3 seconds after the lightning flash is seen. If the speed of sound in air is 340 m/s, how far away did the lightning strike? (Ignore the time taken by light.)