If you want to tune a guitar string to a higher frequency, you should
a) increase the tension in the string.
b) decrease the tension in the string.
c) replace the string with a longer one.
d) replace the string with a more massive one.

i dont know sorry

step-by-step explanation:

sounds & other waves originate from any vibrating object

i'm assuming that it's c.)   volcanoes built the mountains and earthquakes tore them down.

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.