In the Constitution of the United States of America, which amendment primarily protects freedom of expression, including freedom of speech and of the press?

Introduction / Context:
This question focuses on comparative constitutional knowledge, particularly the United States Bill of Rights. Many exams in general knowledge and political science expect students to know which American constitutional amendment protects freedom of expression. Although the Indian Constitution uses Articles rather than amendments for fundamental rights, the United States First Amendment is internationally famous for its strong protection of free speech and free press.

Given Data / Assumptions:

• The context is the Constitution of the United States of America.
• The right in question is freedom of expression, including speech and press.
• The options provide different amendment numbers.

Concept / Approach:
The Bill of Rights is the collective name for the first ten amendments to the United States Constitution. The First Amendment is especially important because it prohibits Congress from making laws that abridge freedom of speech, freedom of the press, freedom of religion, freedom of assembly and the right to petition the government for redress of grievances. This amendment has shaped American political culture and many landmark judicial decisions about what counts as protected speech.

Step-by-Step Solution:
Step 1: Recall that the Bill of Rights consists of the first ten amendments, with each amendment dealing with different rights. Step 2: Identify which specific amendment talks about freedom of religion, speech, press, assembly and petition. Step 3: Remember that this cluster of rights is in the First Amendment. Step 4: Check the options and locate the First Amendment as option A. Step 5: Select the First Amendment as the correct answer.
Verification / Alternative check:
An alternative check is to recall other well known amendments: the Nineteenth Amendment is about women's suffrage, giving women the right to vote; the Twelfth Amendment modifies the procedure for electing the President and Vice President; the Ninth Amendment states that listing certain rights in the Constitution does not deny others retained by the people. None of these describe freedom of expression, confirming that the First Amendment is the correct one.

Why Other Options Are Wrong:
Option B (Twelfth Amendment) deals with the electoral process for President and Vice President and has nothing to do with free speech or expression.
Option C (Ninth Amendment) recognises that rights not specifically mentioned in the Constitution may still exist, but it does not itself spell out freedom of expression in the direct way the First Amendment does.
Option D (Nineteenth Amendment) is about voting rights regardless of sex and specifically enabled women to vote in the United States, not about speech or press.

Common Pitfalls:
Students sometimes mix up amendment numbers, especially if they have only a vague idea of the American Bill of Rights. Another pitfall is confusing the United States constitutional scheme with the Indian scheme, where freedom of speech and expression is guaranteed by Article 19 of the Constitution of India, not by numbered amendments. Carefully reading the question's reference to the United States avoids such confusion.

Final Answer:
In the United States Constitution, freedom of expression is primarily protected by the First Amendment.