An ant is on the pendulum bob of the clock. What would be the displacement in one time period?

At the end of one full time period, the ant has returned to where it was at the beginning of the time period. Its displacement is zero.

mistakes are ok

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.