Which of the following best explains the relationship between peak to peak amplitude and semi amplitude

Which of the following best explains the relationship between peak-to-peak amplitude and semi-amplitude? Semi-amplitude is half the distance of the peak-to-peak amplitude. Semi-amplitude is the same distance as the peak-to-peak amplitude.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.