The cart is going left is your answer
What are the "following" devices ? ?
I think they're a list of choices that you have but aren't sharing.
A few devices associated with the reception of various types of
radio signals include the resonant tank, the local oscillator, the
mixer, the detector, the coherer, the discriminator, the parabolic
reflector, the lecher wires, the audio transducer, the demultiplexer,
and ... my personal guess ... the 'antenna' or 'aerial'.
Mercury has less mass than earth. So the answer is B
