Humans cannot synthesize which of the following Polyunsaturated Fatty Acids (PUFA) in their bodies?

Correct option is A

Option (a): Correct
• Linoleic acid (Omega-6) is an essential fatty acid because humans lack the enzyme Δ12-desaturase needed to synthesize it.
• It must be obtained from diet.
Option (b): Incorrect
• DHA can be synthesized in small amounts from α-linolenic acid, though inefficiently.
Option (c): Incorrect
• Arachidonic acid can be synthesized from linoleic acid if essential fatty acids are available.
Option (d): Incorrect
• EPA can be synthesized in small amounts from α-linolenic acid.
Hence, only linoleic acid is strictly essential.