Which of the Following Is a Reasonable Explanation as to Why

Multiple Choice

Which of the following is a reasonable explanation as to why atomic radii become smaller as one moves to the right for the representative elements in a period?

A) The charge of the nucleus increases, pulling the shells closer.
B) More densely packed shells are always smaller.
C) Elements become less metallic.
D) Atomic radii actually increase as you move to the right.