Which of the Following Statements About Congressional Districts in the House

Which of the following statements about congressional districts in the House of Representatives is accurate?

A) The size of the House continues to increase every 10 years since the Constitution requires 1 representative for every 33,000 residents.
B) States have only gained seats following the decennial census and never lost them.
C) Population movements have meant that states in the south and the west have gained seats at the expense of industrial states in the northeast and Midwest.
D) The Constitution requires that the geographic size of each congressional district needs to be substantially similar.