Explain the meaning of the following :a) magnetic field​

A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. ... A permanent magnet′s magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets

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.