I think the answer is A because the job of a cell membrane is to provide protection to the plant. A cell membrane has a sturdy wall.
M CH₃COOH: 12u×2 + 1u×4 + 16u×2 =<u> 60u</u>
m 9CH₃COOH: 60u×9 = <u>540u</u>
<em>(1u ≈ 1,66·10⁻²⁴g)</em>
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1u ------- <span>1,66·10⁻²⁴g
540u ---- X
X = 540</span>×<span>1,66·10⁻²⁴g
<u>X = 896,4</u></span><span><u>·10⁻²⁴g
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