The correct answer is Metal.
Sound waves are vibrations which need medium to propagate. Higher the density of medium, the sound travels fastest. Sound travels fastest in solid than liquid and gas. Therefore, in this question sound will travel faster in metal because metal has higher density than air and water and it will not travel in vacuum as sound needs medium to travel.
<span>DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups alternating.</span>
I am mostly sure the answer is B. Good luck, and sorry if it's wrong! :(
Answer: could you be more specific what is your question
Explanation: