**Core Concept**
Polysaccharides and proteins are the two primary types of antigens. However, polysaccharides are generally better antigens due to their unique chemical properties and the way they interact with the immune system.

**Why the Correct Answer is Right**
Polysaccharides are better antigens because they can induce a T-cell independent immune response. This is because polysaccharides can directly bind to and activate B cells without the need for T-cell help. This results in the production of IgM antibodies, which are the first line of defense against pathogens. In contrast, proteins require T-cell help to activate B cells and induce a T-cell dependent immune response.

**Why Each Wrong Option is Incorrect**
**Option A:** Peptides are short chains of amino acids and are not typically considered antigens on their own. They often require processing and presentation by antigen-presenting cells to induce an immune response.
**Option B:** Nucleic acids can act as antigens, but they are not typically as effective at inducing an immune response as polysaccharides. This is because nucleic acids are often degraded by enzymes and do not activate B cells directly.
**Option C:** Lipids are not typically considered antigens, although some lipids can be recognized by the immune system as part of a larger molecule.

**Clinical Pearl / High-Yield Fact**
When considering the chemical nature of an antigen, remember that polysaccharides are generally better at inducing a T-cell independent immune response, while proteins require T-cell help to activate B cells.

**Correct Answer:** C. Lipids are not typically considered antigens, although some lipids can be recognized by the immune system as part of a larger molecule.