Oxidation and Reduction Statements Evaluation Steps:

• Identify the statements: 1 (oxidation loses electrons), 2 (reduction gains electrons), 3 (oxidation increases oxidation number).
• Recall definitions: Oxidation is loss of electrons or increase in oxidation number; reduction is gain of electrons or decrease in oxidation number.
• Evaluate statement 3: It incorrectly states oxidation increases oxidation number without noting reduction decreases it, but the phrasing may be ambiguous or wrong.
• Conclude correct statements are 1 and 2 based on standard definitions.

Why A is correct:

• Statements 1 and 2 align with the core definition of redox reactions where oxidation involves electron loss and reduction involves electron gain.

Why the others are wrong:

• B includes 3, which misstates oxidation number change without full context.
• C excludes 1, omitting the fundamental electron loss in oxidation.
• D includes all, but 3 is incorrect or incomplete.

Not enough information. Final answer: Not enough information.