Question

Brian was researching an old form of communication that used sound as signals. Which could be the form of communication Brian was researching?

A.the use of smoke signals to send messages
B.the use of varied flags to send messages
C.the use of carrier pigeons to deliver notes
D. the use beating drums to send warnings

Answer 1

D

Step-by-step explanation:

drums make sound

Answer 2

Your answer would be D, as it is the only thing that generates sound out of the 4 answers.