Question

what did we observe when we looked at the speaker up close?
o it was not making any sound
o it was connected to the truck
o it was making a loud noise
o it was moving back and forth

Explanation:

The image shows sound - wave patterns around the speaker, indicating it was making a sound. So we can rule out the option of it not making any sound. There is no indication of it moving back and forth or not being connected to the truck.

Answer:

It was making a loud noise