Final answer:
The U.S. flag should never touch the ground or floor, which is a rule to show respect for the flag as a national symbol. Options A, C, and D are incorrect. Flag burning, despite being controversial, is protected as free speech under the First Amendment.
Step-by-step explanation:
The question, "The flag of the United States of America should never:", pertains to the proper etiquette and rules governing the treatment of the U.S. flag. The correct answer to the options given is B) Touch the ground or floor. This is a rule to show respect to the flag as a symbol of the nation. On the other hand, A) is not a recognized rule, C) is incorrect as the flag may be displayed in all weather conditions if it is made of an all-weather material, and D) is fundamentally wrong since altering the flag's design would be contrary to the official specifications.
In terms of desecration, which includes burning the flag, although controversial, is considered a form of free speech protected under the First Amendment. There have been legislative efforts and proposals for a Flag Desecration Amendment to give Congress the power to outlaw such acts, but these efforts have not succeeded in passing a constitutional amendment.