four charges for the +q,+q,-q,-q are placed respectively at the four corners of a square of side a find the magnitude and direction of the electric field at the centre of the square

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.

third one with arrows on top of each other going the same direction