Fig. 2.1 shows a sign that extends over a road. The mass of the sign is 8000 kg. The weight of the sign acts at a horizontal distance of 1.8m from the centre of the support post and it produces a turning effect about point P. Point P is a horizontal distance of 1.3m from the centre of the support post

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.

'b ' is the correct conclusion.