The plasma membrane is a bilayer. lipid phospholipid carbohydrate protein

Option B. "Phospholipid"

Explanation:

Plasma membrane is a biological membrane that covers the outermost layer of the organism. It's composition varies in some of bacterial cells but most of them are made up of phospholipid bilayer.

Phoshpolipid bilayer are amphiphilic in nature with two hydrophobic fatty acid tails and one hydrophilic phosphate head.

It's main function is it acts a barrier to keep the proteins other molecules and ions out of the cell and diffuses them across this membrane when it is require.

Thus, the correct answer is phospholipid.

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