Saturated fatty acids follow C_nH_{2n}O_2 formula

Steps:

• Recall general formula for saturated fatty acids: C_nH_{2n}O_2, indicating no C=C double bonds.
• For A (C₁₅H₃₀O₂): compute 2×15=30 hydrogens, matches exactly.
• For B (C₁₇H₃₄O₂): compute 2×17=34 hydrogens, matches but exceeds typical even-chain length.
• For C and D: fewer hydrogens than 2n indicate double bonds (unsaturation).

Why A is correct:

• Matches C_nH_{2n}O₂ definition precisely for n=15, representing a saturated chain with maximum hydrogens.

Why the others are wrong:

• B: Matches formula but for odd-length chain uncommon in standard fatty acids; A is intended.
• C: 28 hydrogens vs. expected 30 for n=15, indicating one double bond (unsaturated).
• D: 32 hydrogens vs. expected 34 for n=17, indicating one double bond (unsaturated).

Final answer: A