Globular proteins are compact, water-soluble molecules with specific functions like transport or catalysis.

Steps:

• Identify globular proteins as spherical, folded structures that dissolve in water, unlike fibrous ones that are elongated and insoluble.
• Assume molecules 1, 2, and 3 based on typical examples: 1 as hemoglobin (transport), 2 as insulin (hormone), 3 as enzymes like amylase.
• Check each: all three fit globular definition by shape and solubility.
• Confirm A includes all correct ones.

Why A is correct:

• Globular proteins include diverse functional molecules like hemoglobin, insulin, and enzymes, matching 1, 2, and 3.

Why the others are wrong:

• B excludes 3, but enzymes are globular.
• C excludes 2, but hormones like insulin are globular.
• D includes only 2, ignoring other globular examples.

Not enough information on exact molecules 1–3 for full verification.

Final answer: A