About how many times stronger than the 1.5v battery is the 6.0v battery?

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).

the answer is b i think

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.