To determine which of the options are not fatty acids, we need to understand the nature of each compound mentioned:

Glutamic acid (A): This is an amino acid, not a fatty acid. Amino acids are the building blocks of proteins and have a structure completely different from that of fatty acids.

Arachidonic acid (B): This is a polyunsaturated omega-6 fatty acid, commonly found in the phospholipids of the cell membranes.

Palmitic acid (C): This is a saturated fatty acid that is commonly found in animals and plants. It is one of the most common fatty acids in body lipids.

Lecithin (D): Also known as phosphatidylcholine, lecithin is not a fatty acid but a fatty substance consisting of phospholipids. It is a major component of cell membranes.

Aspartic acid (E): This is another amino acid, not a fatty acid. Similar to glutamic acid, it is part of proteins and has a distinct structure from that of fatty acids.

Based on the information above:

Glutamic acid (A), Lecithin (D), and Aspartic acid (E) are not fatty acids.

Therefore, the correct option is:

Option C: A, D and E only